LIBRARY  OF  THE  UNIVERSITY  OF  CALIFORNIA. 


GIPT 
MISS  ROSE  WHITING. 


Deceived  September,  i8g6. 
Accession  No.#J}  y*J0  3-         Class  No. 


i 


A  POPULAK 


TREATISE   0^    GEMS 


<5^   ^ 

7^4  /     X? 


Entered  according  to  Act  of  Congress,  in  the  year  1S69. 
BY  DK.  L.  FEUCIITW^NGEE, 

In  th*  Clerk's  Office  of  the  District  Court  of  the  United  States  for  the  Southern 
District  of  New  York. 


JOHN  W.  AMEBMAN,  PRINTKK, 
No.  4T  Cedar  St.,  N.  Y. 


PREFACE 


IN  none  of  the  numerous  works  on  Mineralogy  that  have 
lately  been  published,  have  GEMS  been  treated  in  a  manner 
commensurate  with  the  important  rank  which  they  hold  in  the 
mineral  kingdom.  The  author  of  this  treatise  published  in 
1838  a  small  work  on  Gems,  which  was  well  received  by  the 
scientific  world.  As  that  edition  was  soon  disposed  of,  the 
author  intended  to  issue  a  larger  and  improved  edition,  but 
close  application  to  his  legitimate  pursuits  prevented  him  from 
accomplishing  that  object.  In  1851  he  visited  the  London 
Exhibition,  where  the  treasures  of  the  mineral  kingdom,  and  the 
profusion  of  brilliant  and  costly  gems  from  all  quarters  of  the 
globe,  formed  a  collection  such  as  had  never  before  been  wit- 
nessed ;  and  he  then  resolved  to  embody  the  facts  which  he 
had  there  collected  in  a  ne\v  work  on  Gems,  which  he  has  been 
encouraged  to  publish  by  the  solicitations  of  numerous  teachers 
and  jewellers,  who  had  used  his  former  treatise  as  a  work  of 
reference,  and  who  wish  to  have  a  work  that  will  impart  useful 
and  correct  information  in  regard  to  tjie  locality  and  value  of 
Gems  in  the  present  state  of  scientific  knowledge.  As  a  work 
on  Gems  would  be  incomplete  without  a  treatise  on  Mineralogy, 
and  as  the  author  did  not  wish  to  enter  into  details  foreign  to 
his  subject,  he  was  at  a  loss  how  to  commence ;  but  on  consult- 
ing the  recent  works  on  the  Elements  of  Mineralogy  of  Pro£ 
Nichols  and  Zimmerman,  he  was  conviiu:<  <1  that  a  summary 


PREFACE. 

of  the  leading  principles  of  Mineralogy  was  indispensable,  as  ar 
introduction  to  his  main  design ;  and  that  Crystallography,  the 
mother  of  Gems,  should  be  explained,  before  treating  them  when 
prepared  for  the  dealer  or  wearer  :  he  concluded,  therefore,  to 
commence  his  treatise  by  following  the  Terminology  of  Nichols' 
Elements  of  Mineralogy,  of  which  he  copied  the  greater  part, 
along  with  some  remarks  of  Dufresnoy,  from  the  study  of  whose 
great  work  on  Mineralogy  he  derived  much  valuable  informa- 
tion. He  feels  it  incumbent  on  him  publicly  to  acknowledge 
his  obligations  to  the  author  of  the  Elements  of  Mineralogy, 
for  the  concise  and  lucid  descriptions  contained  in  the  first 
part  of  that  work,  which  should  be  read  by  every  student  of 
Mineralogy.  In  the  second  part  of  this  work,  which  treats  of 
Gems,  the  author  has  followed  his  own  system  in  their  classifi- 
cation j  that  is,  he  has  arranged  them  according  to  their  in- 
trinsic value,  and  not  alphabetically,  as  has  been  done  by  some 
authors,  nor  as  oxydized  stones — a  system  adopted  by  others. 
The  diamond  is  placed  at  the  head  of  the  whole  class  of  Gems, 
and  the  others  follow  in  the  order  of  their  commercial  value. 
Some  minerals  which  are  not  properly  Gems  have  been  in- 
cluded in  the  list,  either  on  account  of  certain  specific  characters 
which  they  possess,  or  their  applicability  to  some  useful  purpose. 
Many  mineral  substances  which  belong  properly  to  the  geolog- 
ical or  economical  department  of  the  science  of  mineralogy, 
have  been  treated  in  this  part  of  the  work ;  but  they  occupy 
so  important  a  position  in  the  economy  of  life,  that  their  intro- 
duction cannot  be  regarded  as  an  intrusion.  Reference  is  here 
made  to  the  detailed  account  of  coal,  marble,  granite,  and 
sienite — are  they  not  as  valuable  as  the  Gems  described  in  this 
treatise  ?  are  they  not  the  foundation  on  which  is  to  be  reared 
the  opulence  of  future  generations?  have  they  not  already 
contributed  to  the  aggrandisement  of  the  United  States,  the 
most  enterprising  nation  on  the  globe  ? 

The  revenue  arising  from  £he  annual  production  of  eight 


PREFACE.  7 

million  tons  of  coal  is  not  inconsiderable.  The  marble  of  the 
country,  which  is  just  beginning  to  be  developed,  bids-  fair  to 
compete  with  that  of  any  other  country,  .and  to  revolutionize 
the  civilized  world.  The  marble  from  California,  that  from 
the  quarry  lately  discovered  in  Pennsylvania,  the  Leocadia 
Breccia,  the  Verde- Antique  of  Vermont,  and  the  white  marble 
from  Canaan,  Conn.,  which  is  used  in  the  construction  of  the 
Fifth  Avenue  Hotel,  Madison  Square,  N.  Y.,*are  referred  to  as 
illustrations.  Are  not  the  sienites  and  the  granites  which 
have,  been  quarried  for  the  last  fifty  years;  and  which  have  been 
used  in  the  erection  of  all  our  public  edifices,  really  as  valuable 
as  Gems  ? 

Few  persons  were  aware,  until  recently,  of  the  existence  of 
fancy  (variegated)  marbles  in  this  country  ;  and  Italy,  Greece, 
and  Ireland  furnish  the  materials  for  ornamenting  fine  houses 
and  cemeteries,  because  our  own  resources  have  been  overlooked, 
or  not  developed.  What  will  be  the  condition  of  things  fifty 
years  hence,  when  the  fine  arts  will  occupy  as  prominent  a  po- 
sition in  this  country  as  in  any  other,  and  when  wealth  and 
taste  will  compete  with  the  arts  and  sciences  for  the  ascendency  ? 
The  Almighty  has  converted  the  vegetables  of  the  forest  into  a 
mineral  substance,  the  animals  of  the  sea  into  building-stone, 
and  endowed  man  with  the  faculty  of  exploring  and  developing 
the  hidden  treasures  of  nature,  and  this  faculty  will  soon  render 
this  country  independent  of  all  other  nations.  The  principal 
aim  .of  the  author  has  been  to  explain  not  only  the  useful,  but 
also  the  ornamental  mineral  substances,  and  such  compositions 
called  mosaics  as  are  prepared  from  them,  and  he  is  indebted 
for  much  valuable  information  pertaining  to  this  branch  of  the  t 
subject  to  the  Jury  Report  of  the  London  Exhibition. 


PEEFACE  TO  THE  THIED  EDITION. 


THE  publication  of  1859  having  been  exhausted  for  several  years, 
the  numerous  applications  from  booksellers  for  a  supply  have  in- 
duced the  author  to  issue  another  edition,  and  to  improve  it  in  add- 
ing an  Appendix  to  the  work  on  such  subjects  which,  in  his  judg- 
ment, was  considered  indispensable ;  it  was  to  give  to  his  readers 
the  chronology  of  mineralogical  knowledge,  from  its  first  dawn  to 
the  present  day,  and  with  much  perseverance  and  labor  he  accom- 
plished this  task.  It  was  thought  advisable  and  useful  to  add  tables 
of  the  distinguishing  characteristics  of  gems,  so  as  to  have  at  one 
glance  a  condensed  survey  of  the  physical  and  chemical  characters 
of  all  the  gems,  and  they  were,  therefore,  copied  from  Mr.  Harry 
Emanuel's  late  work  on  Diamonds  and  Precious  Stones,  as  also 
many  remarks  on  the  value  and  market  prices  of  gems,  etc. 

The  author  was  requested  to  have  his  likeness  placed  in  front  of 
the  work,  and  reluctantly  complied  with  it ;  but  while  doing  so,  he 
is  satisfied  that  his  numerous  friends  on  the  Pacific  will  consider  it 
acceptable.  On  account  of  the  latter  change,  the  former  frontispiece 
had  neeessarily  to  be  altered,  and  the  best  place  was  Part  III.,  where 
the  individual  gems  were  treated  on  page  183,  but  the  Kohinoor 
and  Zircon  crystals  were  deemed  best  to  be  replaced  by  other  gems, 
which  his  friend,  Mr.  G.  CX  Newcomb,  kindly  furnished  him  for  copy- 
•ing ;  they  are  a  large  Ruby  spinelle  of  100  carats  weight,  and  a 
large  Hyacinthe,  and  a  beautiful  precious  Opal,  which  were  photo- 
graphed along  with  various  gems  and  executed  very  faithfully. 

In  the  present  great  Paris  Exposition,  according  to  the  official 
catalogue,  a  great  many  valuable  gems  are  mentioned,  such  as  the 
Crown  Jewels  of  France ;  those  from  the  Queen  of  Sweden ;  also 
those  of  Russia ;  and  from  the  various  English,  German,  Turkish 
and  French  jewellers ;  also,  a  Brazilian  Topaz,  of  3£  Ibs.  weight, 
7£  inches  long  and  4f  inches  wide,  has  recently  been  deposited. 
The  extensive  display  of  Corals,  one  set  of  which  was  valued  at 
$2,300,  and  many  others,  but,  for  want  of  a  detailed  description, 
could  not  be  enumerated  in  this  Treatise. 

The  author  had  latterly  occasion  to  examine  at  the  jewelry  store 
of  Messrs.  Bishop  &  Rein,  under  the  Fifth  Avenue  Hotel,  New- York, 
a  beautiful  white  Brilliant,  of  14  carats  weight,  and  a  great  variety 
of  splendid  pink  Corals.  Also,  at  Doucet's  store,  Montreal,  from 
Thunder  Bay,  Lake  Superior,  large  masses  of  Amethysts,  weighing 
several  hundred  pounds. 

The  author  takes  pleasure  in  recommending  the  Heliographic 
Engraving  Company,  under  the  superintendence  of  Baron  Egloff- 
stein.;  the  author's  likeness  having  been  executed  by  them  with 
much  skill. 

Praise  is  also  due  to  Mr.  Schnapauff,  who  much  improved  the 
oojoring  of  the  gems,  many  of  them  true  to  nature. 

With  these  few  remarks,  the  author  commits  herewith  the  present 
edition  to  the  reader,  and  trusts  it  may  prove  useful  and  instructive, 
which  will  ever  gratify  the  public  servant, 

LEWIS  FEUCHTWANGER,  M.  D. 

NEW-YORK,  June  1, 1867. 


CONTENTS. 


PAG* 

INTRODUCTION 13 

PAET  I. 

TERMINOLOGY. 

CHAPTER  I. — Form  of  minerals 19 

"        II. — Physical  properties  of  minerals 75 

"       in.— Chemical  properties  of  minerals 102 

"       IV.— Classification  of  minerals 129 

PAET   II. 

THE  GEMS. 

Division  of  Gems 135 

Color,  gravity,  and  hardness 137 

Chemical  characters 139 

Composition 139 

Artificial  production  of  Gems  and  Minerals 140 

Geological  characters 145 

Geographical  distribution 146 

Practical  division  and  nomenclature 147 

History  of  Gems 148 

Sculpture  in  Gems 151 

On  Grinding 153 

Forms  of  the  diamond 161 

Form  of  Gems 163 

Common  lapidary .......  166 

Engraving 166 

Sawing  and  drilling  Gems fc 168 

1* 


10  CONTENTS. 

PAGB 

Grinding  and  polishing  materials 168 

Heightening  the  color  of  Gems 169 

Setting  of  Gems 171 

Cleaning  Gems 172 

Imitations  of  Gems 172 

Price  of,  and  trade  in  Gems '. . . .  181 

Gems  for  optical  purposes 181 


PAET  III. 

CONSIDERATION  OF  THE  INDIVIDUAL  GEMS. 

Diamond 183 

Corundum 214 

Sapphire 214 

Common  corundum 223 

Chrysoberyl,  Cymophane 225 

Spinelle 227 

Topaz 229 

Euclase ' 234 

Emerald 235 

Beryl,  aquamarine 240 

Zircon,  Hyacinth,  Jargon 244 

Garnet 247 

Essonite,  Cinnamon -stone 253 

Tourmaline,  Kubellite,  Siberite 254 

Quartz 259 

Kock  crystal 260 

Amethyst 266 

Common  quartz — rose  quartz 269 

"            "         Cat's  eye 270 

"            "         Prase 271 

"            "         Avanturine 272 

Jasper 273 

Hornstone .....' 277 

Chalcedony 277 

Carnelian 279 

Heliotrope,  Bloodstone 282 

Agate 283 

Chrysoprase 292 


CONTENTS.  11 

PAGB 

Chrysolite,  Peridot,  Olivin 294 

Isolite 297 

Opal 299 

Fire  opal 304 

Hydrophane 305 

Semi-opal m 306 

Cachelong 307 

Jasper  opal 308 

Obsidian 309 

Axinite % 311 

Felspar 312 

Adularia 312 

Common  felspar  315 

Labrador 317 

Hypersthene 320 

Idocrase 321 

Hauyne 322 

Lapis  lazuli 322 

Kyanite,  Sappare,  Disthene 327 

Turquoise 329 

Natrolite 332 

Fluor  spar , 333 

Malachite .336 

Satin  spar 340 

Alabaster 341 

Amber , 343 

Jet 353 

Meerschaum 357 

Lava , 360 

Jade ;  361 

Serpentine -. 362 

Marble 364 

Stalactite  and  Stalagmite 380 

Egyptian  and  Italian  marbles 382 

American  marbles 383 

Pisolite  and  Oolite 386 

Rock  of  Gibralter 386 

Apatite 387 

Lepidolite 389 

Mica..                                                                                                  .  389 


12  CONTENTS. 

PA  08 

Pyrites ... .. 390 

Kose  manganese 391 

Porphyry 391 

Sienite 393 

Granite 396 

Pearls , 400 

Corals ......... 419 

Shell  cameos : 425 

Mosaic  and  Pietra  Dura..  .  426 


INTRODUCTION. 


THE  natural  productions  of  our  globe  may  be  considered 
either  in  their  original  or  in  their  changed  condition.  They 
are  divided  into  two  general  classes  which  are  determined, 
—either  by  certain  characters  that  do  not  require  explana- 
tion or  investigation, — or,  by  the  external  appearances 
which  are  presented  by  them  in  their  altered  condition, 
and  by  investigating  the  causes  which  produced  the  changes 
of  form  or  state. 

In  the  former  case,  the  science  is  called  Natural  History; 
in  the  latter,  Natural  Philosophy. 

Natural  History,  considered  in  reference  to  the  original 
properties  of  natural  productions,  must,  therefore,  be  di- 
vided into  organic  and  inorganic:  to  the  former  belong 
Zoology  and  Botany ;  to  the  latter,  Mineralogy. 

Botany  and  Zoology  comprise  bodies  possessed  of  vitality, 
or  beings  which,  increasing  by  the  absorption  of  nutritive 
substances,  mature  after  a  certain  period ;  their  parts  are 
dependent  upon  each  other,  and  they  cannot  be  separated 
without  destroying  the  integrity  of  the  individual,  which, 
after  a  certain  period,  loses  its  vitality  and  ceases  to  exist ; 


14  INTRODUCTION. 

or  death  ensues,  decomposition  takes  place,  and  the  original 
being  is  entirely  destroyed. 

Mineralogy,  on  the  contrary,  comprises  those  natural 
objects  which  are  not  possessed  of  life,  and  do  not  increase 
by  absorption,  but  merely  by  accretion — that  is,  by  an  ex- 
ternal growth  or  addition  without  any  assimilation ;  they 
do  not  mature  by  age  ;  their  parts  may  be  separated  with- 
out destroying  their  individuality;  and  their  formation 
being  the  result  of  chemical  attraction,  they  are  not  liable 
to  decomposition. 

Mineralogy  comprises  two  distinct  sciences :  Mineralogy 
proper,  which  treats  of  the  simple  minerals,  either  as  inde- 
pendent bodies,  or  in  relation  to  the  characters  which  serve 
to  determine  and  distinguish  them ;  and  G.eology,  which 
considers  both  simple  and  mixed  minerals  as  they  exist  in 
nature,  and  in  their  dependent  relations  with  soils  and 
rocks.  Mineralogy  describes  the  individual  qualities  of  the 
several  mineral  species, — Geology  treats  of  them  only-  as 
associated  in  the  structure  of  the  earth. 

The  characters  of  minerals  are  ascertained  by  their  mor- 
phological, physical,  and  chemical  properties.  That  part  of 
Mineralogy  which  treats  of  the  application  of  minerals  to 
the  different  arts,  is  called  Economical  Mineralogy ;  miner- 
als used  by  lapidaries  in  making  ornaments,  are  called  Gems. 

Geometry,  Physics  (Natural  Philosophy),  and  Chemistry, 
form  the  base  for  the  study  of  Mineralogy,  as  without  a 
knowledge  of  those  sciences,  the  true  characters  of  a  min- 
eral cannot  be  ascertained. 

Geology  is,  according  to  Lyell's  explanation,  the  science 
which  investigates  the  successive  changes  that  have  taken 
place  in  the  organic  and  inorganic  kingdoms  of  nature.  It 


INTRODUCTION.  •  15 

inquires  into  the  causes  of  these  changes,  and  the  influence 
which  they  have  exerted  in  modifying  the  surface  and  ex« 
temal  structure  of  our  planet.  By  these  researches  into 
the  state  of  the  earth  and  its  inhabitants  at  former  periods, 
we  acquire  a  more  perfect  knowledge  of  its  present  condi- 
tion, and*  more  comprehensive  views  concerning  the  laws 
now  governing  its  animate  and  inanimate  productions. 
When  we  study  history,  we  obtain  a  more  profound  in- 
sight into  human  nature,  by  instituting  a  comparison  be- 
tween the  present  and  former  states  of  society.  We  trace 
the  long  series  of  events  which  have  gradually  led  to  the 
actual  posture  of  affairs,  and  by  connecting  effects  with 
their  causes,  we  are  enabled  to  classify  and  retain  in  the 
memory  a  multitude  of  complicated  relations,  the  various 
peculiarities  of  national  character,  the  different  degrees  of 
moral  and  intellectual  refinement,  and  numerous  other  cir- 
cumstances, which,  without  historical  associations,  would 
be  uninteresting  or  imperfectly  understood.  When  we 
carry  back  similar  relations  into  the  history  of  nature,  we 
likewise  investigate  nature's  operations  in  former  epochs. 

The  form  of  a  coast,  the  configuration  of  the  interior  of 
a  country,  the  existence  and  extent  of  lakes,  valleys,  and 
mountains,  can  often  be  traced  to  the  former  prevalence  of 
earthquakes  and  volcanoes  in  regions  which  have  long  been 
undisturbed.  To  these  remote  convulsions  the  present  fer- 
tility of  some  districts,  the  sterile  character  of  others,  the 
elevation  of  land  above  the  sea,  the  climate,  and  various 
peculiarities,  may  be  distinctly  referred.  Many  distinguish- 
ing features  of  the  surface  of  the  earth  may  often  be  as- 
cribed to  the  operation,  at  a  remote  era,  of  slow  and  tran- 
quil causes,  to  the  gradual  deposition  or  sediment  in  a  lake 


16  INTRODUCTION. 

or  in  the  ocean,  or  to  the  prolific  increase  of  testacea  and 
corals.  "We  also  find  in  certain  localities  subterranean  de- 
posits of  coal,  consisting  of  vegetable  matter  formerly 
drifted  into  seas  and  lakes.  These  seas  and  lakes  have 
since  been  filled  up,  the  lands  whereon  the  forests  grevt 
have  disappeared  or  changed  their  form,  the  rivers  and 
currents  which  floated  the  vegetable  masses  can  no  longer 
be  traced,  and  the  plants  belonged  to  species  which  for  ages 
have  passed  away  from  the  surface  of  our  planet,  yet  the 
commercial  prosperity  and  numerical  strength  of  a  nation 
may  now  be  mainly  dependent  on  the  local  distribution  of 
fuel  determined  By  that  ancient  state  of  things.  Geology 
is  intimately  connected  to  almost  all  physical  sciences,  as 
history  is  to  the  moral.  An  historian  should,  if  possible, 
be  profoundly  acquainted  with  ethics,  politics,  jurispru- 
dence, the  military  art,  theology,  and  with  all  branches  of 
knowledge,  by  which  an  insight  into  human  affairs,  or  into 
the  moral  and  intellectual  nature  of  man,  can  be  obtained. 
No  less  desirable  is  it  for  a  geologist  to  be  well  versed  in 
chemistry,  natural  philosophy,  mineralogy,  zoology,  com- 
parative anatomy,  botany,  and  every  science  relating  to 
organic  and  inorganic  nature.  Having  such  accomplish- 
ments, the  historian  and  geologist  would  rarely  fail  to  draw 
correct  and  philosophical  conclusions  from  the  various 
monuments  transmitted  to  them  from  former  occurrences. 
They  would  know  to  what  combination  of  causes  analogous 
effects  were  referable,  and  would  often  be  enabled  to  sup- 
ply by  inference  information  concerning  many  events  unre- 
corded in  the  defective  archives  of  former  ages. 

Mineralogy  is  sometimes  understood  as  comprising  the 
natural  history  of  every  portion  of  inorganic  nature.    Here 


INTRODUCTION.  17 

we  consider  it  as  limited  to  the  natural  history  of  simple 
minerals,  or  mineral  species.  In  the  strictest  sense,  a  min- 
eral species  is  a  natural  inorganic  body,  possessing  a  defi- 
nite chemical  composition,  and  assuming  a  regular  deter- 
minate form,  or  series  of  forms.  Many  substances  hereto- 
fore regarded  as  minerals  will  naturally  be  excluded — such 
as  all  the  artificial  salts,  the  inorganic  secretions  of  plants 
and  apimals,  the  remains  of  former  living  beings  now  im- 
bedded in  rocks.  Many  substances  originally  organic  pro 
ducts  have  by  common  consent  found  a  place  in  mineral 
systems — such  as  coal,  amber,  and -mineral  resins — which 
ought  not  to  be  the  case ;  also  some  amorphous  substances, 
with  no  forms  or  chemical  composition,  a*s  some  kinds  of 
clay,  have  also  been  introduced  into  works  on  Mineralogy, 
but  often  improperly,  and  with  no  beneficial  result.  Aggre- 
gates of  simple  minerals  or  rocks  are  likewise  excluded  from 
the  science  of  Mineralogy,  though  the  various  associations 
of  minerals,  their  modes  of  occurrence,  and  their  geologi- 
cal position,  are  important  points  in  the  history  of  the  dif- 
ferent species.  One  most  important  object  in  Mineralogy  is 
a  full  description  of  minerals,  their  essential  properties  and 
distinctive  characters,  as  will  enable  the  student  to  distin- 
guish the  various  species,  and  to. recognize  them  when  they 
occur  in  nature. 

The  gems,  or  precious  stones,  are  obtained  from  miner- 
als. It  is  indispensable,  therefore,  to  be  fully  acquainted 
with  all  the  characters  which  distinguish  them  from  one 
another,  which  is  accomplished  by  the  terminology  or  no- 
menclature of  the  science  of  Mineralogy — that  is,  with  the 
meaning  of  the  terms  used  in  describing  the  properties  of 
minerals,  and  the  various  modifications  they  may  undergo, 


18 

and  also  an  account  of  the  properties  themselves.  The 
system  of  classification  is  another  closely  related  portion  of 
Mineralogy.  It  gives  an  account  of  the  order  in  which  the 
mineral  species  are  arranged.  A  third  and  most  important 
part  of  Mineralogy  is  the  physiography  of  the  various 
species — giving  an  account  of  their  characteristic  marks, 
and  a  description  of  their  appearance  or  external  aspect 
and  forms,  their  principal  physical  and  chemical  properties, 
their  mode  of  occurrence,  with  their  geological  and  geo- 
graphical distribution,  and  their  various  uses,  whether  in 
nature  or  whether  in  tne  arts,  or  as  gems  for  ornamental 
purposes, 


PART  I. 

TERMINOLOGY. 


CHAPTER  I. 
FORM   OF    MIXERAIS. 

THE  physical  properties  of  a  mineral  comprise  all  those 
properties  belonging  to  it  as  a  body  existing  in  space,  and 
consisting  of  matter  aggregated  in  a  peculiar  way.  The 
more  important  of  these  are, — its  form  as  shown  in  crystal- 
lization ;  its  structure  as  determining  its  mode  of  cleavage 
and  fracture ;  its  hardness  and  tenacity ;  its  weight  or  spe- 
cific gravity ;  and  its  relations  to  light,  heat,  electricity,  and 
magnetism. 

Crystalline  and  Amorphous. — Mineral  substances  occur 
'in  two  distinct  modes  of  aggregation.  Some  consist  of 
minute  particles  simply  collected  together,  with  no  regu- 
larity of  structure  or  constancy  of  External  form,  and  are 
named  amorphous.  All  fluid  minerals  are  in  this  condition, 
together  with  some  solid  bodies,  which  appear  to  have  con- 
densed either  from  a  gelatinous  condition  like  opal,  when 
they  are  named  porodine,  or  from  a  state  of  igneoue  fluidity 
like,  obsidian  and  glass,  when  they  are  named  hyalite.  The 
other  class  have  their  ultimate  atoms  evidently  arranged 
according  to  definite  law,  and  are  named  crystallim.,  when 
the  regulai  ity  of  structure  appears  only  in  the  internal  «*is- 


20  A  PRACTICAL  TREATISE  ON  GEMS. 

position  of  the  parts  ;  and  crystallized,  when  it  also  produces 
a  determinate  external  form,  or  a  crystal. 


CRYSTALS. 

Faces,  Edges,  Angles,  Axes  of  Crystals. — The  word 
crystal  in  mineralogy  designates  a  solid  body  exhibiting  an 
original  (not  artificial)  more  or  less  regular  polyhedric  form. 
It  is  thus  bounded  by  plane  surfaces,  named  faces,  which 
intersect  in  straight  lines  OY. edges,  and  these  again  meet  in 
points .  and  form  solid  angles,  bounded  by  three  or  more 
faces.  The  space  occupied  by  a  crystal  is  often  named  a 
form  of  crystallization,  which  is  thus  the  mathematical 
figure  regarded  as  independent  of  the  matter  that  fills  it. 
Crystals  bounded  by  equal  and  similar  faces  are  named 
simple  forms  /  while  those  in  which  the  faces  are  not  equal 
and  similar  are  named  compound  forms,  or  combinations, 
being  regarded  as  produced  by  the  union  or  combination  of 
two  or  more  simple  forms.  The  cube  or  hexahedron  (fig. 
1),  bounded  by  six  equal  and  similar  squares;  the  octahe- 
dron (fig.  2),  by  eight  equilateral  triangles ;  and  the  rhom- 
bohedron,  by  six  rhombs, — are  thus  simple  forms.  An  axis 
of  a  crystal  is  a  line  -passing  through  its  centre  and  termi- 
nating either  in  the  middle  of  two  faces,  or  of  two  edges,  or 
in  two  angles ;  and  axes  terminating  in  similar  parts  of  a 
crystal  are  named  similar  axes.  In  describing  a  crystal,  one 
of  its  axes  is  supposed  to  be  vertical  or  upright,  and  is  then 
named  the  principal  axis,  and  that  axis  is  chosen  which  is 
the  only  one  of  its  kind  in  the  figure.  A  few  other  techni- 
cal terms  used  in  describing  crystals  will  be  explained  as 
they  occur.  .  . 

Systems  of  Crystallization. — The  forms  of  crystals  that 
occur  in  nature  seem  almost  innumerable.  On  examining 
them,  however,  more  attentively,  certain  relations  are  dis- 


FORM    OF    MINERALS. 


21 


covered  even  between  highly  complex  crystals.  When  the 
axes  are  properly  chosen,  and  placed  in  a  right  position,  the 
various  faces  are  observed  to  group  themselves  in  a  regular 
and  beautiful  manner  around  these  axes,  and  to  be  all  so 
related  as  to  compose  connected  series  produced  according 
to  definite  laws.  In  every  mineral  species  there  is  a  certain 
form  of  crystal  from  which,  as  a  primary,  every  other  form 
of  crystal  observed  in  that  mineral  species  may  be  deduced. 
In  each  species  the  axes,  bearing  to  each  other  definite 
numerical  proportions,  intersect  at  angles  which  are  constant. 
So  also  the  faces  of  the  various  forms  are  related  to  each 
other,  and  to  their  primary,  according  to  certain  definite 
laws.  When  viewed  in  this  manner,  amd  referred  to  their 
simplest  forms,  the  innumerable  variety  of  crystals  occurring 
in  nature  may  all  be  reduced  to  six  distinct  groups,  or,  as 
they  are  named,  systems  of  crystallization.  The  following 
are  the  names  given  to  these  systems  of  crystallization  in 
some  of  the  best  authors : 


Naumann. 

1.  Tesseral  System. 

2.  Tetragonal  System. 
8.  Hexagonal  System. 

4.  Rhombic  System." 

5.  Monoclinohedric  System. 

6.  Triclinohedric  System. 


In  the  following  treatise  the  terminology  of  Naumann  is 
adopted,  his  method  of  classifying  and  describing  crystals 
appearing  the  simplest  and  best  adapted  to  promote  the 
progress  of  the  student. 

Holohedric  and  Hemihedric. — Before  describing  these 
systems,  it  must  be  observed  that  certain  crystals  appear  as 
the  half  of  others,  and  are  therefore  named  hemihedric ; 
while  the  crystals  with  the  full  number  of  faces  are  named 
holohedric.  Hemihedric  crystals  are  formed  when  the  alter- 


Mobs. 
Tessular. 
Pyramidal. 
Rhoinbohedral. 
Orthotype. 
Hemiorthotype. 
Anprthotype. 

Weiss  and  G.  Eose; 
Regular. 
2  and  1  axial. 
3  and  1  axial. 
1  and  /I  axial. 
2  and  1  membered. 
1  and  1  membered. 

22 


A   PRACTICAL  TREATISE   ON    GEMS. 


nate  faces  or  groups  of  faces  of  a  holohedric  crystal  increase 
symmetrically,  so  as  to  obliterate  the  other  faces.  Thus, 
if  four  alternate  faces  of  the  octohedron  increase  so  as  to 
obliterate  the  other  four,  a  tetrahedron  with  half  the  num- 
ber of  faces  is  formed. 

I.  The  first,  or  Tesseral  System,  named  from  tessera,  a 
cube,  wliich  is  one  of  the  most  frequent  varieties,  is  charac- 
terized by  three  equal  axes  intersecting  each  other  at  right 
angles.  Properly  speaking,  this  system  has  no  chief  axis, 
as  any  one  of  them  may  be  so  named,  arid  placed  upright 
in  drawing  and  describing  the  crystals.  Of  these  there  are 
thirteen  varieties,  which  are  thus  classed  and  named  from 
the  number  of  their  faces : 

1.  One  Tetrahedron,  or  form  with  four  faces. 

2.  One  Hexahedron,  with  six  faces. 

3.  One  Octahedron,  with  eight  faces. 

4.  Four  Dodecahedrons,  with  twelve  faces. 

5.  Five  Icosi tetrahedrons,  with  twenty-four  faces. 
6.r  One  Tetracontaoctahedron,  with  forty-eight  faces. 

The  dodecahedrons  are  further  distinguished,  according 
to  the  form  of  their  faces,  into  rhombic,  trigonal,  deltoid, 
and  pentagonal  dodecahedrons ;  and  some  of  the  icositetra- 
hedrons  have  also  received  peculiar  names. 


Fig.1. 


Fig.  2 


FORM    OF    MINERALS. 


23 


The  following  is  a  description,  with  figures,  of  the  differ- 
ent forms  above  mentioned,  beginning  with 
The  Hololiedric  forms. 

1.  The  hexahedron  or  cube  (fig.  1)  is  bounded  by  sax 
equal  squares,  has  twelve  edges,  formed  by  faces  meeting 
at  90°,  and  eight  trigonal  angles.     The  principal  axes  join 
the  centre  points  of  any  two  opposite  faces. — Examples  are 
fluor  spar,  galena,  boracite. 

2.  The  octahedron  (fig.  2),  bounded  by  eight  equilateral 
triangles,  has  twelve  equal  edges,  with  planes  meeting  at 
109°  28',  and    six  tetragonal  angles.  *  The  principal  axes 
join  the  opposite  angles,  two  and  two. — Example,  alum, 
spinel,  magnetic  iron  ore. 

3.  The  rhombic-dodecahedron  (fig.   3)  is  bounded   by 
twelve  equal  and  similar  rhombs  (diagonals  as  1  andv^2), 


Fig.* 


Fig.  4. 


has  twenty-four  equal  edges  of  120°,  and  six  tetragonal  and 
eight  trigonal  angles.  The  principal  axes  join  two  opposite 
tetragonal  angles. — Ex.,  garnet,  boracite. 

4.  The  tetrakishexahedrons  (variety  of  icositetrahedron, 
fig.  4)  are  bounded  by  twenty-four  isosceles  triangles,  ar- 
ranged in  six  groups  of  four  each.  They  have  twelve  longer 
edges  which  correspond  to  those  of  the  primitive  or  in- 


24          A  PRACTICAL  TREATISE  ON  GEMS. 

scribed  tube,  and  twenty-four  shorter  edges  placed  over 
each  of  its  faces.  The  angles  are  eight  hexagonal  and  six 
tetragonal ;  the  latter  joined  two  and  two  by  the  three  prin- 
cipal axes.  This  form  varies  in  general  aspect,  approach- 
ing, on  the  one  hand,  to  the  cube  ;  on  the  other,  to  the  rhom- 
bic-dodecahedron.— Ex.,  fluor  spar,  gold. 

5.  The  triakisoctahedrons  (variety  of  icositetrahedron, 
fig.  5)  are  bounded  by  twenty-four  isosceles  triangles,  in 
eight  groups  of  three,  and,  like  the  previous  form,  vary  in 
general  aspect  from  the  octahedron  on  one  side,  to  the 
rhombic-dodecahedron  on  .the  other.  The  edges  are  twelve 
longer,  corresponding  with  those  of  the'  inscribed  octahe- 
dron, and  twenty-four  shorter,  three  and  three  over  each 
of  the  faces.  The  angles  are  eight  trigonal  and  six  dite- 
tragonal  (formed  by  eight  faces)  ;  the  latter  angles  joined 
two  and  two  by  the  principal  axes. — Ex.,  galena,  diamond. 


Fig.  5.  Fig.  6. 

6.  The  icositetrahedrons  (most  common  variety,  fig.  6) 
are  bounded  by  twenty-four  deltoids  or  figures  with  .four . 
sides,  of  which  two  and  two  adjacent  ones  are  equal.  This 
form  varies  from  the  octahedron  to  the  cube,  sometimes 
approaching  the  former  and  sometimes  the  latter  in  general 
jispect.  The  edges  are  twenty-four  longer  and  twenty- 
four  shorter.  The  angles  are  six  tetragonal  joined  by  the 


FORM    OF   MINERALS.  25 

principal  axes,  eight  trigonal,  and  twelve  rhombic,  or  tetra- 
gonal with  unequal  angles. 

7.  The  hexakisoctahedrons  (fig.  7),  bounded  by  forty- 
eight  scalene  triangles,  vary  much  in  general  aspect,  ap- 
proaching more  or  less  to  all  the  preceding  forms ;  but 
most  frequently  they  have  the  face?  arranged  either  in  six 
groups  of  eight,  or  eight  of  six,  or  twelve  of  four  faces. 
There  are  twenty-four  long  edges,  often  corresponding  to 
those  of  the  rhombic-dodecahedron  ;  twenty-four  interme- 
diate edges  lying  in  pairs  over  each  edge  of  the  inscribed 
octahedron  ;  and  twenty-four  short  edges  in  pairs  over  the 
edges  of  the  inscribed  cube.  There  are  six  ditetragonal 
angles  joined  by  the  principal  axes,  eight  hexagonal  and 
twelve  rhombic  angles. — Ex.,  fluor  spar,  garnet,  diamond. 


Fig.  7. 

The  seven  forms  of  crystals  now  described  are  related  to 
each  other  in  the  most  intimate  manner.  This  will  appear 
more  distinctly  from  the  following  account  of  the  derivation 
of  the  forms,  with  which  is  conjoined  an  explanation  of  the 
crystallographic  signs  or  symbols  by  which  they  are  desig- 
nated. We  have  adopted  these  symbols  throughout  this 
work,  in  the  belief  that  they  not  only  mark  the  forms  in  a 
greatly  abbreviated  manner,  but  also  exhibit  the  relations 
of  the  forms  and  combinations  in  a  way  which  words  could 
hardly  accomplish. 


26  A   PRACTICAL   TREATISE    OX    GEMS. 

The  derivation  of  forms  is  -that  process  by  which,  from 
one  form  chosen  for  the  purpose,  and  considered  as  the 
type — the  fundamental  or  primary  form — all  the  other 
forms  of  a  system  may  be  produced,  according  to  fixed  prin- 
ciples or  general  laws.  In  order  to  understand  this  process 
or  method  of  derivation,  the  student  should  keep  in  mind 
that  the  position  of  any  plane  is  fixed  when  the  positions 
of  any  three  points  in  it,  not  all  in  one  straight  line,  are 
known.  To  determine  the  position,  therefore,  of  the  face 
of  a  crystal,  it  is  only  necessary  to  know  the  distance  of 
three  points  in  it  from  the  centre  of  the  crystal,  or  the 
points  in  which  the  face  or  its  supposed  extension  would  in- 
tersect the  three  axes  of  the  crystal.  The  portion  of  the 
axes  between  this  point  and  the  centre  are  named  parame- 
ters, and  the  position  of  the  face  is  sufficiently  known  when 
the  relative  length  or  proportion  of  these  parameters  is 
ascertained.  When  the  position  of  one  face  of  a  simple 
form  is  thus  fixed  or  described,  all  the  other  faces  are  in 
like  manner  fixed,  since  they  are  all  equal  and  similar,  and 
all  intersect  the  axes  in  a  uniform  manner ;  and  the  expres- 
sion which  marks  or  describes  one  face,  marks  and  describes 
the  whole  figure. 

The  octahedron  is  generally  adopted  as  the  primary  or 
fundamental  form  of  the  tessera!  system,  and  distinguished 
by  the  first  letter  of  the  name,  O.  Its  faces  cut  the  half 
axes  at  equal  distances  from  the  centre  ;  so  that  these  semi- 
axes,  or  the  parameters  of  the  faces,  have  to  each  other  the 
proportion  1:1:1.  In  order  to  derive  the  other  forms 
from  the  octahedron,  the  following  construction  is  em- 
ployed. The  numbers  refer  to  the  descriptions  above. 

Suppose  a  plane  so  placed  in  each  angle  of  the  octahe- 
dron as  to  be  vertical  to  the  axis  passing  through  that 
angle  and  consequently  parallel  to  the  two  other  axes  (or 
to  cut  them  at  an  infinite  distance  =  00);  then  the  hexa- 


FORM    OF   MINERALS.  27 

hedron  or  cube  (l)  is  produced,  designated  by  the  crystal- 
lographic  sign  oo  O  oo  ;  expressing  the  proportion  of  the 
parameters  of  its  faces,  or  oo  :  oo  :  1.  If  a  plane  is  sup- 
posed placed  in  each  edge  parallel  to  one  axis,  and  cut- 
ting the  two  other  axes  at  equal  distances,  the  resulting 
figure  is  the  rhombic  dodecahedron  (3),  designated  by  the 
sign  oo  O,  the  proportion  of  the  parameters  of  its  faces  be- 
ing oo  :  1  :  1.  The  triakisoctahedron  (5)  arises  when  on 
each  edge  of  the  octahedron  planes  are  placed  cutting  the 
axis  not  belonging  to  that  edge  at  a  distance  from  the  cen- 
tre m  which  is  a  rational  number  greater  than  1.  The 
proportion  of  its  parameters  is  therefore  mil  :  1,  and  its 
sign  mO ;  the  most  common  varieties  being  f  O,  2O,  and 
3O.  When,  on  the  other  hand,  from  a  similar  distance  m 
in  each  two  semiaxes  prolonged,  a  plane  is  drawn  to  the 
other  semiaxis,  or  to  each  angle,  an  ikositetrahedron  (6)  is 
formed  ;  the  parameters  of  its  faces  have  consequently  the 
proportion  m  :  1  :  m,  and  its  sign  is  mOm  •  the  most  com- 
mon varieties  being  2O2  and  303,  the  former  very  frequent 
in  leucite,  analcime,  and  garnet.  When,  again,  planes  are 
drawn  from  each  angle,  or  the  end  of  one  semiaxis  of  the 
octahedron,  parallel  to  a  second  axis,  and  cutting  the  third 
at  a  distance  rc,  greater  than  1,  then  the  tetrakishexahedron 
(4)  is  formed,  the  parameter  of  its  faces  oo  :  1  :  n ;  its  sign 
3>On;  and  the  most  common  varieties  in  nature  ooOf, 
oc  O2,  and  oo  O3.  Finally,  if  in  each  semiaxis  of  the  octa- 
hedron two  distances,  m  and  ft,  be  taken,  each  greater  than 
1,  and  m  also  greater  than  n,  and  planes  be  drawn  from 
each  angle  to  these  points,  so  that  the  two  planes  lying 
over  each  edge  cut  the  second  semiaxis  belonging  to  that 
edge,  at  the  smaller  distance  n,  and  the  third  axis  at  the 
greater  distance  m,  then  the  hexakisoctahedron  (7)  is  pro- 
duced, the  parameters  of  which  are  m  :  n  :  1,  its  sign  mOn, 
and  the  most  common  varieties  3Of,  4O2,  and  5Of . 


28  A  PRACTICAL  TREATISE  ON  GEMS. 

The  next  class  of  crystals  are  the  semi- tesseral  form,s ;  and 
first,  those  with  oblique  faces,  often  named  tetrahedral,  from 
their  relation  to  the  tetrahedron.  (1.)  This  form  (fig.  8) 


Fig.  8.  Fig.  9. 

is  bounded  by  four  equilateral  triangles,  has  six  equal  edges 
with  faces  meeting  at  70°  32 ',  and  four  trigonal  angles. 
The  principal  axes  join  the  middle  points  of  each  two  op- 
posite edges. — Ex.,  gray-copper  ore,  boracite,  and  helvine. 
(2.)  The  trigonal  dodecahedrons  (fig.  9)  are  bounded  by 
twelve  isosceles  triangles,  and  vary  in  general  form  from 
the  tetrahedron  to  the  hexahedron.  There  are  six  longer 
edges  corresponding  to  those  of  the  inscribed  tetrahedron, 
and  twelve  shorter  placed  three  and  three  over  each  of  its 
faces  ;  and  four  hexagonal  and  four  trigonal  angles. — Ex., 
gray-copper  ore,  and  bismuth-blende.  (3.)  The  deltoid- 
dodecahedrons  (fig.  10)  are  bounded  by  twelve  deltoids, 
and  vary  in  general  form  from  the  tetrahedron  on  the  one 
hand,  to  the  rhombic-dodecahedron  on  the  other.  They 
have  twelve  longer  edges  lying  in  pairs  over  the  edges  of 
the  inscribed  tetrahedron ;  and  twelve  shorter  edges,  three 
and  three  over  each  of  its  faces.  The  angles  are  six  tetra- 
gonal (rhombic),  four  acute  trigonal,  and  four  obtuse  tri- 
gonal angles.  The  principal  axes  join  two  and  two  oppo- 
site rhombic  angles. — Ex.,  gray-copper  ore.  (4.)  The  hex- 
akistetrahedrons  (fig.  11)  are  bounded  by  twenty-four 


FORM   OF   MINERALS.  29 

scalene  triangles,  and  most  commonly  have  their  faces 
grouped  in  four  systems  of  six  each.  The  edges  are  twelve 
shorter  and  twelve  longer,  lying  in  groups  of  three  over 


Fig.  10.  Fig.  11. 

each  face  of  the  inscribed  tetrahedron,  and  twelve  interme 
diate  in  pairs  over  its  edges.  The  angles  are  six  rhombic, 
joined  in  pairs  by  the  principal  axes,  and  four  acuter  and 
four  obtuser  hexagonal  angles. — Ex.,  diamond. 

The  derivation  and  signs  of  these  forms  are  as  follows : — 
The  tetrahedron  arises  when  four  alternate  faces  of  the 
octahedron  are  enlarged,  so  as  to  obliterate  the  other  four, 

and  its  sign  is  hence  — .     But,  as  either  four  faces  may  be 

thus  enlarged  or  obliterated,  two  tetrahedrons  can  be  formed 
similar  in  all  respects  except  in  position,  and  together  mak- 
ing up  the  octahedron.  These  are  distinguished  by  the 
signs  +  and  — ,  added  to  the  above  symbol,  but  only  the 

latter  in  general  expressed  thus .     In  ah1   hemihedric 

systems  two  forms  similarly  related  occur,  which  may  thus 
be  named  complementary  forms.  The  trigonal  dodecahe- 
dron is  derived  from  the  icositetrahedron,  by  the  expansion 

of  the  alternate  trigonal  groups  of  faces.    Its  sign  is  — - — , 


30 


A    PRACTICAL   TREATISE    ON    GEMS. 


2O2 
the  most  common  variety  being ,  found  in  gray-copper 

ore.  The  deltoid-dodecahedron  is  in  like  manner  the  result 
of  the  increase  of  the  alternate  trigonal  groups  of  faces  of  the 

triakisoctahedron,  and  its  sign  is .     Lastly,  the  hexakis- 

tetrahedron  arises  in  the  development  of  alternate  hexa- 
gonal groups  of  faces  in  the  hexakisoctahedron,  and  its  sign 
.  mOn 

~' 

The  parallel-faced  semitesseral  forms  are  two.  (1.)  The 
pentagonal  dodecahedrons  (fig.  12)  are  bounded  by  twelve 


Fig.  12. 


Fig.  13. 


symmetrical  pentagons,  and  vary  in  general  aspect  be- 
tween the  hexahedron  and  rhombic-dodecahedron.  They 
have  six  regular  (and  in  general  longer)  edges,  lying 
over  the  faces  of  the  inscribed  hexahedron,  and  twenty- 
four  generally  shorter  (seldom  longer)  edges,  usually  lying 
in  pairs  over  its  edges.  The  angles  are  eight  of  three  equal 
angles,  and  twelve  of  three  unequal  angles.  Each  princi- 
pal axis  unites  two  opposite  regular  edges.  This  form  is 

derived  from  the  tetrakishexahedron,  and  its  sign  is , 

one  of  the  most  common  varieties  being  ,  found  fre- 

quently in  iron  pyrites  and  cobaltine.     (2.)  The  dyakisdo- 


FORM    OF    MINERALS.  31 

decahedron  (fig.  13),  bounded  by  twenty-four  trapezoids 
with  two  sides  equal,  has  twelve  short,  twelve  long,  and 
twenty-four  intermediate  edges.  The  angles  are  six  equi- 
angular rhombic,  united  in  pairs  by  the  principal  axes,  eight 
trigonal,  and  twenty-four  irregular  tetragonal  angles.  It  is 

derived  from  the  hexakisoctahedron,  and  its  sign  is  F  '—— ,  J 
the  brackets  being  used  to  distinguish  it  from  the  hexakiste- 


Fig.  14.  Fig.  15. 

trahedron,  also  derived  from  the  same  primary  form.  It 
occurs  in  iron  pyrites  and  cobaltine.  There  are  two  other 
tetrahedral  forms,  the  pentagonal  dodecahedron  (fig.  14), 
and  the  pentagonal  icositetrahedron  (fig.  15),  both  bounded 
by  irregular  pentagons,  but  not  yet  observed  in  nature. 

Combinations. — These  forms  of  the  tesseral  system  (and 
this  is  true  also  of  the  five  other  systems  of  crystallization) 
not  only  occur  singly,  but  often  two,  three,  or  more  are  united 
in  the  same  crystal,  forming  what  are  named  combinations. 
In  this  case  it  is  evident  that  no  one  of  the  individual  forms 
can  be  completely  developed,  because  the  faces  of  one  form 
must  partially  interfere  with  the  faces  of  the  other  forms. 
A  combination  therefore  implies  that  the  faces  of  one  form 
shall  appear  symmetrically  disposed  between  the  faces  of 
other  forms,  and  consequently  in  the  room  of  certain  of 
their  edges  and  angles.  These  edges  and  angles  are  thus, 


32  A   PRACTICAL   TREATISE    ON    GEMS. 

as  it  were,  cut  off,  and  new  ones  produced  in  their  place, 
which  properly  belong  neither  to  the  one  form  nor  the  other, 
but  are  edges  or  angles  of  combination.  Usually,  one  form 
predominates  more  than  the  others,  or  has  more  influence  on 
the  general  aspect  of  the  crystal,  and  hence  is  distinguished 
as  the  predominant  form,  the  others  being  named  subordi- 
nate. The  following  terms  used  on  this  subject  require  ex- 
planation. A  combination  is  developed  when  all  the  forms 
contributing  to  its  formation  are  pointed  out ;  and  its  sign 
consists  of  the  signs  of  these  forms,  written  in  the  order  oi 
their  influence  on  the  combination,  with  a  point  between. 
An  angle  or  edge  is  said  to  be  replaced  when  it  is  cut  ofl 
by  one  or  more  secondary  planes ;  it  is  truncated  when  cut 
by  one  plane,  forming  equal  angles  with  the  adjacent  faces ; 
and  an  edge  is  bevelled  when  replaced  by  two  planes,  which 
are  equally  inclined  to  the  adjacent  faces. 

It  will  be  readily  seen  that  such  combinations  may  be 
exceedingly  numerous,  or  rather  infinite ;  and  only  a  few 
of  the  more  common  can  be  noticed,  simply  as  specimens 
of  the  class.  Many  others  more  complicated  will  occur  in 
the  descriptive  part  of  this  treatise.  Among  plenotesseral 
combinations,  the  cube,  octahedron,  and  also  the  rhombic- 
dodecahedron,  are  the  predominant  forms.  In  fig.  16  the 


Fig.  16.  Fig.  17. 

cube  has  its  angles  replaced  by  the  faces  of  the  octahedron, 
and  the  sign  of  this  combination  is  ooOoo  .  O.  In  fig.  17 
this  process  may  be  regarded  as  having  proceeded  still  fur- 


FORM    OF    MINERALS. 


33 


ther,  so  that  the  faces  of  the  octahedron  now  predominate, 
and  the  sign,  of  the  same  two  elements  but  in  reverse  order, 
is  O  .  ooOoo.  In  fig.  18  the  cube  has  its  edgesre  placed 


Fig.  la  Fig.  19. 

by  the  faces  of  the  rhombic-dodecahedron,  the  sign  being 
oo Goo  .  ccO;  while  in  fig.  19  there  is  the  same  combina- 
tion, but  with  the  faces  of  the  cube  subordinate,  and  hence 
the  symbol  is  ooO  .  ooOoo  .  The  former  figure,  it  will  be 
seen,  has  more  the  general  aspect  of  the  cube ;  the  latter  of 
the  dodecahedron. 

In  combinations  of  semitesseral  forms  with  oblique  faces, 
the  tetahedron,  the  rhombic-dodecahedron,  or  even  the 
hexahedron,  seldomer  a  trigonal-dodecahedron,  are  the  more 


Fig.  20. 


Fig.  2L 


common  predominant  forms.     In  fig.  20  two  tetrahedrons 

in  opposite  positions,  —  •— -^  are  combined.     In  fig.  21  a 
2* 


34 


A  PRACTICAL  TREATISE  ON  GEMS. 


very  complex  combination  of  seven  forms  is  represented  in 
a  crystal  of  gray-copper  ore,  its  full  sign  being  — 


(0  .ooOcc  (/)  .  ^0(o). 

the  letters  in  brackets  connecting  them  with  the  respective 
faces  of  the  figure.  As  examples  of  combinations  of  semi- 
tesseral  forms  with  parallel  faces,  we  may  take  fig.  22,  in 


Fig.  22.  Fig.  23. 

which  each  of  the  angles  of  the  cube  is  unsymmetrically 
replaced  by  three   faces  of  the  dyakisdodecahedron,  and 

hence    ccOoo  .   I  —  I  ;  or  fig.  23,  in  which  the  pentagonal- 
dodecahedron  has  its  trigonal  angles  replaced  by  the  faces 

oo02 

of  the  octahedron,  consequently  with  the  sign  • .  O. 

Figure  24  represents  the  same  com- 
bination but  with  greater  predomi- 
nance of  the  faces  of  the  octahedron, 
the  crystal  being  bounded  by  eight 
equilateral  and  twelve  isosceles  tri- 
angles. 

II.  Tetragonal  System. — This  sys- 
tem has  three  axes  at  right  angles, 


Fig.  24. 


two  of  them  equal  and  one  unequal.  The  last  is  the  princi- 
pal axis,  and  when  it  is  brought  into  a  vertical  position  the 
crystal  is  said  to  be  placed  upright.  Its  ends  are  named 


FORM    OF    MINERALS.  38 

poles,  and  the  edges  connected  with  them  polar  edges.  The 
two  other  axes  are  named  subordinate  or  lateral  axes,  and 
a  plane  passing  through  them  is  named  the  basis  of  the 
crystal.  The  two  planes  that  pass  through  the  principal 
and  one  of  the  lateral  axes  are  named  normal  chief  sections, 
and  a  plane  through  the  chief  axis  intermediate  to  them,  a 
diagonal  chief  section.  The  name  tetragonal  is  derived 
from  the  form  of  the  basis,  which  is  usually  quadratic. 

There  are  eight  tetragonal  forms,  of  which  five  are  closed, 
— that  is,  bounded  on  ah1  sides  by  planes,  and  of  definite 
extent, — and  three  open,  which  in  certain  directions  are  not 
bounded,  and  consequently  of  indefinite  extent. 

The  description  of  the  varieties  is  as  follows,  it  being 
premised  that  a  crystallographic  pyramid  is  equivalent  to 
two  geometrical  pyramids  joined  base  to  base. 


Fig.  25.  Fig.  26. 

Closed  forms. — (1.)  Tetragonal  pyramids  (figs.  25,  26)  are 
inclosed  by  eight  isosceles  triangles,  with  four  middle  edges 
all  in  one  plane,  and  eight  polar  edges.  There  are  three 
kinds  of  this  form,  distinguished  by  the  position  of  the  lat- 
eral axes.  In  the  first  these  axes  unite  the  opposite  angles  ; 
in  the  second  they  intersect  the  middle  edges  equally; 


»C  A   PRACTICAL   TREATISE    ON    GEMS. 

and  in  the  third  they  lie  in  an  intermediate  position,  or 
divide  these  edges  unequally ;  the  latter  being  hemihedral 
forms.  These  pyramids  are  also  distinguished  as  obtuse 
(fig.  25)  or  acute  (fig.  26),  according  as  the  vertical  angle 
is  greater  or  less  than  in  the  octahedron,  which,  though 
intermediate,  is  never  a  tetragonal  form.  (2.)  Ditetragonal 
pyramids  (fig.  27)  are  bounded  by  sixteen  scalene  triangles, 


Fig.  27. 


Fig.  28. 


whose  base  lines  are  all  in  one  plane.  This  form  rarely 
occurs  except  in  combinations.  (3.)  Tetragonal  sphenoids 
(fig.  28),  bounded  by  four  isosceles  triangles,  are  the  hemi- 
hedral forms  of  the  first  variety  of  tetragonal  pyramids. 
(4.)  The  tetragonal  scalenohedron  (fig.  29),  bounded  by 
eight  scalene  triangles,  whose  bases  rise  and  fall  in  a  zig-zag 
line,  is  the  hemihedral  form  of  the  ditetragonal  pyramid. 
The  latter  two  forms  are  rare. 

Open  forms. — Tetragonal  prisms  (fig.  30)  bounded  by 
four  planes  parallel  to  the  principal  axis;  ditetragonal 
prisms  by  eight  similar  planes.  In  these  prisms  the  prin- 
cipal axis  is  supposed  to  be  prolonged  infinitely,  or  to  be 
unbounded.  Where  it  is  very  short  and  the  lateral  axes 


FORM    OF   MINERALS. 


87 


infinite,  the  basal  piriacoid  is  formed,  consisting  merely  ot 
two  parallel  faces. 

The  various  series  of  tetragonal  crystals  are  distinguished 
from  each  other   only  by  their  relative   dimensions.    To 


Fig.  29. 


Fig.  80. 


determine  these,  one  of  the  series  must  be  chosen  as  the 
fundamental  form,  and  for  this  purpose  a  tetragonal  pyramid 
of  the  first  variety,  designated  by  P  as  its  sign,  is  selected. 
The  angle  of  one  of  its  edges,  especially  the  middle  edge, 
found  by  measurement,  determines  its  angular  dimensions  ; 
while  the  proportion  of  the  principal  axis  (a)  to  the  lateral 
axes  supposed  equal  to  1,  gives  its  linear  dimensions.  The 
parameters,  therefore,  of  each  face  of  the  fundamental  form 
are  1  :  1  :  a. 

Now  if  m  be  any  (rational)  number,  either  less  or  greater 
than  1,  and  if  from  any  distance  ma  in  the  principal  axis 
planes  be  drawn  to  the  middle  edge  of  P,  then  new  tetra- 
gonal pyramids  of  the  first  kind,  but  more  or  less  acute  or 
obtuse  than  P,  are  formed.  The  general  sign  of  these 
pyramids  is  mP,  and  the  most  common  varieties  ^P,  2P, 
3P ;  with  the  chief  axis  equal  to  ^,  twice  or  thrice  that  of 
P.  If  m  becomes  infinite,  or  =  o>,  then  the  pyramid  passes 
into  a  prism,  indefinitely  extended  along  the  principal  axis, 


A  PBACTICAL  TREATISE  ON  GEMS. 


and  with  the  sign  ooP;  if  m=0,  which  is  the  case  when 
the  lateral  axes  are  supposed  infinite,  then  it  becomes  a 
pinacoid,  consisting  properly  of  two  basal  faces,  open  to- 
wards the  lateral  axes,  and  designated  by  the  sign  OP.  The 
ditetragonal  pyramids  are  produced  by  taking  in  each  lateral 
axis  distances  n  greater  than  1,  and  drawing  two  planes  to 
these  points  from  each  of  the  intermediate  polar  edges. 
The  parameters  of  these  planes  are  therefore  m  :  I  :  n,  and 
the  general  sign  of  the  form  mPn,  the  most  common  values 
of  n  being  J,  2,  3,  and  oo.  When  n  =  oo,  a  tetragonal 
pyramid  of  the  second  kind  arises,  designated  generally  by 
mP  oo,  the  most  common  in  the  mineral  kingdom  being  P  oo 
and  2P  oo.  The  relation  of  these  to  pyramids  of  the  first 


Fig.  81. 


Fig.  32. 


kind  is  shown  in  fig.  31,  where  ABBBX  is  the  first,  and 
ACCCX  the  second  kind  of  pyramid.  In  like  manner  from 
the  prism  ooP,  the  ditetragonal  prisms  ooPn  are  derived, 
arid  finally  when  n  =  oo,  the  tetragonal  prism  of  the  sec- 
ond kind,  whose  sign  is  oopoo  . 

The  combinations  of  the  tetragonal  system  are  either 
holohedric  or  hemihedric  ;  but  the  latter  are  rare.  Prisms 
and  pinacoids  must  always  be  terminated  on  the  open  sides 
by  other  forms.  Thus  in  fig.  32  a  square  prism  of  the  first 
kind  is  terminated  by  the  primary  pyramid,  and  has  its 


FORM    OF    MINERALS. 


39 


lateral  angles  again  replaced  by  another  more  acute  pyra- 
mid of  the  second  kind,  so  that  its  sign  is  ooP  .  P  .  2Poo. 
In  fig.  33  a  prism  of  the  second  kind  is  first  bounded  by 


Fig.  33. 


Fig.  84. 


the  fundamental  pyramid,  and  then  has  its  edges  of  combi- 
nation replaced  by  a  ditetragonal 
pyramid,  and  its  sign  is  here 
ooPoo .  P  .  3P3.  In  fig.  34  the 
polar  edges  of  the  pyramid  are 
replaced  by  another  pyramid,  its 
sign  being  P.  Poo .  In  fig.  35  a 
hemihedric  form  very  characteris- 
tic of  copper  pyrites  is  represented, 
P  and  P'  being  the  two  sphenoids,  Fis- ;35- 

a  the  basal  pinacoid,  and  5,  c,  two  ditetragonl  pyramids. 

III.  The  Hexagonal  System. — The  essential  character  of 
this  system  is,  that  it  has  four  axes, — three  equal  lateral  axes 
intersecting  each  other  in  one  plane  at  60°,  and  one  principal 
axis  at  right  angles  to  them.  The  extremities  of  the  prin- 
cipal axis  are  named  poles,  and  sections  through  it  and  one 
lateral  axis,  normal  chief  sections.  The  plane  through  the 
lateral  axes  is  the  basis,  and  from  its  hexagonal  form  gives 
the  name  to  the  system.  As  in  the  last  system,  its  forms 
are  either  closed  or  open  /  and  are  divided  into  holohedral, 


40 


A    PRACTICAL    TREATISE    ON    GEMS. 


hemihedral,  and  tetartohedral, — the  last  forms  with  only  a 
fourth  part  of  their  faces  developed.  The  tetartohedral  and 
many  of  the  hemihedral  forms  are  of  rare  occurrence,  and 
only  a  few  of  the  more  common  require  to  be  here  described. 
The  hexagonal  pyramids  (figs.  36,  37)  are  bounded  by 
twelve  isosceles  triangles,  and  are  of  three  kinds,  according 


Fig.  36. 


Fig.  37. 


as  the  lateral  axes  fall  in  the  angles,  in  the  middle  of  the 
lateral  edges,  or  in  another  point  of  these  edges,  the  latter 
being  hemihedral  forms.  They  are  also  classed  as  acute 
or  obtuse,  but  without  any  very  precise  limits.  The  trigo- 
nal pyramid  is  bounded  by  six  triangles,  and  may  be  viewed 
as  the  hemihedral  form  of  the  hexagonal.  The  dihexago- 
nal  pyramid  is  bounded  by  twenty-four  scalene  triangles, 
but  has  never  been  observed  alone,  and  rarely  even  in  com- 
binations. The  more  common  prisms  are  the  hexagonal  of 
six  sides,  and  the  dihexagonal  of  twelve  sides. 

As  the  fundamental  form  of  this  system,  a  particular  pyr- 
amid P  is  chosen,  and  its  dimensions  determined  either 
from  the  proportion  of  the  lateral  to  the  principal  axis 
(1  :  a),  or  from  the  measurement  of  its  angles.  From  this 
form  (mP)  others  are  derived  exactly  as  in  the  tetragonal 


POKM    OF    MINERALS. 


41 


system.  Thus  dihexagonal  pyramids  are  produced  with 
the  general  sign  wPn,  the  chief  peculiarity  being  that, 
whereas  in  the  tetragonal  system  n  might  have  any  rational 
value  from  1  to  oo,  in  the  hexagonal  system  it  can  only 
vary  from  1  to  2,  in  consequence  of  the  geometric  charac- 
ter of  the  figure.  When  n=2  the  dihexagonal  changes 
into  an  hexagonal  pyramid  of  the  second  kind,  whose  sign 
is  raP2.  When  m  is  =  oo  various  prisms  arise  from  similar 
changes  in  the  value  of  n ;  and  when  w=0,  the  basal  pina- 
coid. 

Few  hexagonal  mineral  species  form  perfect  holohedric 
combinations.    Though  quartz  and  apatite  appear  as  such, 


Fig.  33. 


Fig.  39. 


yet  properly  the  former  is  a  tetartohedral,  the  latter  a  hem- 
ihedral  species.  In  holohedric  species  the  predominant 
faces  are  usually  those  of  the  two  hexagonal  prisms  ooP 
and  oo P2,  or  of  the  pinacoid  OP;  while  the  pyramids  P 
and  2P2  are  the  most  common  subordinate  forms.  Figure 
38  represents  the  prism,  bounded  on  the  extremities  by  two 
pyramids ;  one,  P,  forming  the  point,  the  other  2P2,  the 
rhombic  faces  on  the  angles,  or  ocP  .  P  .  2P2.  In  some 
crystals  the  lateral  edges  of  the  prism  are  replaced  by  the 


42  A  PRACTICAL  TREATISE  ON  GEMS. 

second  prism  o>P2,  producing  an  equiangular  twelve-sided 
prism,  which  always  represents  the  combination  ooP.  ooP2, 
and  cannot  occur  as  a  simple  form.  An  example  of  a  more 
complicated  combination  is  seen  in  fig.  39,  of  a  crystal 
of  apatite,  whose  sign  with  the  corresponding  letters  is 
ooP2(e)  .  OP(P)  .  $P(r)  .  P(»)  .  2P(z)  .  P2(«)  . 


Hexagonal  minerals  more  frequently  crystallize  in  those 
series  of  hemihedral  forms  that  are  named  rhombohedral, 
from  the  prevalence  in  them  of  rhombohedrons.  These 
are  bounded  by  six  rhombs  (fig.  40),  whose  lateral  edges  do 


Fig  40. 

not  lie  in  one  plane,  but  vise  and  fall  in  a  zig-zag  manner. 
The  principal  axis  unites  the  two  trigonal  angles,  formed  by 
three  equal  plane  angles,  and  in  the  most  common  variety 
the  secondary  axes  join  the  middle  points  of  two  opposite 
edges.  When  the  polar  edges  form  an  angle  of  more  than 
90°,  the  rhombohedrons  are  named  obtuse ;  when  of  less, 
acute.  Hexagonal  scalenohedrons  (fig.  41)  are  bounded 
by  twelve  scalene  triangles,  whose  lateral  edges  do  not  lie 
in  one  plane.  The  principal  axis  joins  the  two  hexagonal 
angles,  and  the  secondary  axes  the  middle  points  of  two 
opposite  lateral  edges. 

The  rhombohedron  is  derived  from  the  first   kind   of 
hexagonal  pyramid  by  the  hemihedric  development  of  its 

alternate  faces.    Its  general  sign  should  therefore  be  — —  ; 

2 


FORM    OF    MINERALS. 


43 


but  on  several  grounds  it  is  found  better  to  designate  it  by 
R  or  raR,  and  its  complimentary  figure  by  —  niR.  When 
the  prism  or  pinacoid  arise  as  its  limiting  forms,  they  are 
designated  by  ooR  and  OR,  though  in  no  respect  changed 
from  the  limiting  forms  00  P  and  OP  of  the  pyramid.  The 
scalenohedron  is  properly  the  hemihedric  form  of  the 
dihexagonal  pyramid,  but  is  better  derived  from  the 
inscribed  rhombohedron  mR.  If  the  halves  of  the  prin- 
cipal axis  of  this  are  multiplied  by  a  definite  number  n^ 


Fig.  41. 

and  then  planes  drawn  from  the  extremities  of  this  enlarged 
axis  to  the  lateral  edges  of  the  rhombohedron,  as  in  figure 
42,  the  scalenohedron  is  constructed.  Hence  it  is  desig- 
nated by  wiR",  the  n  being  written  on  the  right  hand,  like 
an  algebraic  exponent :  and  the  dihexagonal  prism  is  in 
like  manner  designated  by  ooR". 


44 


A  PRACTICAL  TREATISE  ON  GEMS. 


The  combinations  of  rhombohedric  forms  are  very  nu- 
merous, some  hundreds  being  described  in  calc-spar  alone. 
Among  the  more  common  is  the  prism  in  combination  with 
a  rhombohedron,  as  in  the  twin  crystal  of  calc-spar  (fig.  43), 


Fig.  48. 


Fig.  44. 


with  the  sign  coR.  —  iR,  the  lower  half  being  the  same 
form  with  the  upper,  but  turned  round  180°.  In  figure 
44,  the  rhombohedron  mR  has  its  polar  edges  replaced  by 


Fig.  45. 


Fig.  46. 


another  rhombohedron  —  JwR ;  and  in  figure  45  its  lateral 
edges  bevelled  by  the  scalenohedron  mR*.     A  more  com- 


FORM    OF    MINERALS. 


45 


plex  combination  of  five  forms  is  represented  in  the  crystal 
of  calc-spar,  fig.  46,  its  sign  with  the  letters  on  the  faces 
being  R5(y) .  R3(r) .  R(P) .  4R(m) .  oo  R(c).  Tetartohedric 
combinations  are  seen  most  distinctly  in  pure  quartz  or  rock- 
crystal,  the  pyramids  of  the  first  kind  appearing  as  rhom- 
bohedrons,  those  of  the  second  kind  as  trigonal  pyramids, 
the  dihexahedral  prisms  as  ditrigonal  prisms,  and  the  prism 
oo  P2  as  a  trigonal  prism.  Most  of  these  forms,  however, 
occupy  but  a  very  subordinate  place  in  the  combinations 
which  consist  essentially  of  the  prism  ooP,  and  the  rhom- 

p 
bohedron  R  —  —. 

IV.  Rhombic  System. — The  rhombic  system  is  charac- 
terized by  three  axes,  all  unequal,  but  at  right  angles  to 
each  other.  One  of  these  is  assumed  as  the  chief  axis, 
when  the  others  are  named  subordinate.  The  plane  pass- 
ing through  the  secondary  axes,  or  the  basis,  forms  a 
rhomb,  and  from  this  the  name  is  derived.  This  system 
comprises  only  a  few  varieties  of  forms  that  are  essentially 
distinct,  and  its  relations  are  consequently  very  simple. 


Fig.  47. 


Fig.  43. 


The  closed  forms  are,— (1st.)    The  rhombic  pyramids 
(figs.  47,  48),  bounded  by  eight  scalene  triangles,  whose 


46 


A  POPULAR  TKEATISE  ON  GEMS. 


lateral  edges  lie  in  one  plane,  and  form  a  rhomb.     They 

have  eight  polar  edges, — four  acute  and  four  more  obtuse. 

— and  four  lateral  edges,  and  six  rhombic  angles,  the  most 

acute  at  the  extremities  of  the  longest  axis.     (2cl)  The 

rhombic  sphenoids  (fig.  49) 

are  bounded  by  four  scalene 

triangles  with  their  lateral 

edges    not    in   one  plane ; 

and  are  a  hemihedric  form 

of  the  rhombic  pyramid  of 

unfrequent  occurrence.  The 

open  forms  again  are, — (3d.) 

Rhombic    prisms   bounded 

by  four  planes  parallel  to  Fig.  49. 

one  of  the  axes  which  is 

indefinitely  extended.     They  are  divided  into  upright  and 

horizontal  prisms,  according  as  either  the  principal  or  one  of 

the  lateral  axes  is  supposed  to  become  infinite.     For  the 

latter  form  the  name  doma  or  dome  has  been  used  ;  and 

two  kinds,  the  macrodome  and  the  brachydome,  have  been 

distinguished.     Rhombic  pinacoids  also  arise  when  one  axis 

becomes =0,  and  the  two  others  are  indefinitely  extended. 

In  deriving  these  forms  from  a  primary,  a  particular 
rhombic  pyramid  P  is  chosen,  and  its  dimensions  determined 
either  from  the  angular  measurement  of  two  of  its  edges, 
or  by  the  linear  proportion  of  its  axes  a :  b:  c\  the  greater 
lateral  axis  b  being  assumed  equal  to  1.  To  the  greater 
lateral  axis  the  name  macrodiagonal  is  frequently  given ; 
to  the  shorter,  that  of  brachydiagonal ;  and  the  two  princi- 
pal sections  are  in  like  manner  named  macrodiagonal  and 
brachydiagonal,  according  to  the  axis  they  intersect.  The 
same  terms  are  applied  throughout  all  the  derived  forms, 
where  they  consequently  mark  only  the  position  of  the 
faces  in  respect  to  the  axes  of  the  fundamental  crystal, 


FORM    OF    MINERALS. 


47 


without  reference  to  the  relative  magnitude  of  the  derived 
axes. 

By  multiplying  the  principal  axis  by  any  rational  num- 
ber m,  greater  or  less  than  1,  a  series  of  pyramids  arise, 
whose  general  sign  is  mP,  and  their  limits  the  prism  and 
pinacoid,  the  whole  series  being  contained  in  this  formula, 

OP rnP P -  mP ooP ;   which  is 

the  fundamental  series,  the  lateral  axes  always  remaining 
unchanged.  From 
each  member  a  new 
series  may,  however, 
be  developed  in  two 
directions  by  increas- 
ing one  or  other 
of  the  lateral  axes. 
When  the  macrodia- 
gonal  is  thus  multi- 
plied by  any  number 
n  greater  than  1,  and 
planes  drawn  from 
the  distance  n  to  the 
polar  edges,  a  new 
pyramid  is  produced, 
named  a  macropyra- 
mid,  with  the  sign 
wP/i,  the  mark  over 
the  P  pointing  out 
the  axis  enlarged. 
When  M=QO  a  ma- 
crodome  results,  with 

the  sign  mPoo  .  If  the  shorter  axis  is  multiplied,  then  bra- 
chypyramids  and  brachydomes  are  produced  with  the  signs 
?nPn  and  mPcc  .  So  also  from  the  prism  ooP,  on  the  one 
side,  numerous  macroprisms  ooP^,  with  the  limiting  ma- 


Fig.  50. 


Fig.  51. 


48 


A  POPULAR  TREATISE  05*  GEMS. 


cropinacoid  coPoo;  on  the  other,  numerous  brachyprisma 
ooPft,,  with  the  limit  form  ooPoo,  or  the  brachypinacoid. 
In  figs.  50,  51,  the  two  domes  are  shown  in  their  relation 
to  the  primitive  pyramid. 

The  pyramids  seldom  occur  independent,  or  even  as  the 
predominant  forms  in  a  combination, — sulphur,  however, 
being  an  exception.  Prisms  or  pinacoids  usually  give  the 
general  character  to  the  crystal,  which  then  appears  either 
in  a  columnar  or  tabular,  or  even  in  a  rectangular  pyramidal 
form.  The  determination  of  the  position  of  these  crystals, 


Fig.  52. 


Fig.  54. 


as  vertical  or  horizontal,  depends  on  the  choice  of  the  chief 
axis  of  the  fundamental  form.  In  the  topaz  crystal  (fig.  52) 
the  brachyprism  and  the  pyramid  are  the  predominant  ele- 
ments, associated  with  the  prism,  its  sign  and  letters  being 
ooP2(Q  .  P(o)  .  ooP(m).  Fig.  53  of  stilbite  is  another  ex- 
ample, the  macropinacoid  co Poo  or  M,  being  combined  with 
the  pyramid  P(?"),  the  brachypinacoid  ooPoo  (T),  and  the 
basal  pinacoid  OP  (P).  Another  instance  is  fig.  54  of  a 
lievrite  crystal,  where  the  brachyprism  and  pyramid  com- 
bine with  the  macrodome,  or  coP2  .  P  .  Poo  .  The  follow- 
ing figures  are  very  common  forms  of  barytes ;  figs.  55  and 


FORM    OF   MINERALS. 


49 


Fig.  55. 


Fig.  53. 


56  being  both  composed  of  the  pinacoid,  a  brachydome,  and 
macrodome,  with  sign  OP 
(c).Poo(/)iPoo(d),the 
variation  in  aspect  arising 
from  the  predominance  of 
different  faces ;  and  fig.  57 
consisting  of  the  macro- 
dome  -|P  oo  ,  the  prism 
a>P(^),  and  the  pinacoid 
OP. 

V.  The  Monodinohe- 
dric  System. — This  system 
is  characterized  by  three 
unequal  axes,  two  of  which 
intersect  each  other  at  an 
oblique  angle,  and  are  cut 
by  the  third  at  right  an- 
gles. One  of  the  oblique 
axes  is  chosen  as  the  chief  axis,  and  the  other  axes  are  then 
distinguished  as  the  orthodiagonal  (right-angled)  and  clino- 
diagonal  (oblique-angled).  The  same  terms  are  applied  to 
the  chief  sections,  and  the  name  of  the  system  refers  to  the 
fact  that  these  two  planes  and  the  base,  together  with  two 
right  angles,  form  also  one  oblique  angle  C. 

The  forms  of  this  system  approach  very  near  to  those  of 
the  rhombic  series,  but  the  inclination  of  the  axes,  even 
when  almost  a  right  angle,  gives  them  a  peculiar  character, 
by  which  they  are  always  readily  distinguished.  Each 
pyramid  thus  separates  into  two  altogether  independent 
forms  or  hemipyramids.  Three  varieties  of  prism  also  oc- 
cur,— vertical,  inclined,  and  horizontal, — with  faces  parallel 
to  the  chief  axis,  the  clinodiagonal  or  the  orthodiagonal. 
The  horizontal  prisms,  like  the  pyramids,  separate  into  two 
independent  partial  forms,  named  hemiprisms  or  hemi- 

3 


Fig.  57. 


50 


A  POPULAR  TREATISE  ON  GEMS. 


domes.  The  inclined  prisms  are  often  designated  clino- 
domes,  the  term  prism  being  restricted  to  the  vertical 
forms.  Orthopinacoids  and  clinopinacoids  are  also  distin- 
guished from  their  position  in  relation  to  the  axes. 

The  monoclinohedric  pyramids  (fig.  58)  are  bounded  by 
A  eight  scalene  triangles  of  two 

kinds,  four  and  four  only  be- 
ing   similar.      Their    lateral 

& 

edges  lie  all  in  one  plane, 
and  the  similar  triangles  are 
placed  in  pairs  on  the  clino- 
diagonal  polar  edges.  The 
two  pairs  in  the  acute  angle 
between  the  orthodiagonal 
and  basal  section  are  desig- 
nated the  positive  hemipyra- 
mid ;  while  the  two  pairs  in 
the  obtuse  angles  of  the  same 
sections  form  together  the  negative  hemipyramid.  But  as 
these  hemipyramids  are  wholly  independent  of  each  other, 
they  are  rarely  observed  combined.  More  frequently  each 
occurs  alone,  and  then  forms  a  prism-like  figure,  with  faces 
parallel  to  the  polar  edges,  and  open  at  the  extremities. 
Hence,  like  all  prisms,  they  can  only  appear  in  combination 
with  other  forms.  The  vertical  prisms  are  bounded  by 
four  equal  faces  parallel  to  the  principal  axis,  and  the  cross 
section  is  a  rhomb ;  the  clinodomes  have  a  similar  form 
and  section ;  while  the  horizontal  prisms  or  domes  have 
unequal  faces,  and  their  section  is  a  rhomboid. 

The  mode  of  derivation  of  these  forms  closely  resembles 
that  of  the  rhombic  series.  A  complete  pyramid  is  as- 
sumed as  the  fundamental  form,  and  designated  =b  P,  in 
order  to  express  the  two  portions  of  which  it  consists.  Its 
dimensioRS  a.re  given  when  the  proportion  of  its  axes  $;£:  c, 


FORM    OF   MINERALS. 


51 


and  the  angular  inclination  of  the  oblique  axes  (7,  which  is 
also  that  of  the  orthodiagonal  section  to  the  basis,  are 

known.      The  fundamental   series  of  forms  is  OP 

dbwP ±P ±mP ooP ;    from  each  of 

whose  members,  by  changing  the  dimensions  of  the  other 
axes,  new  forms  may  be  again  derived.  Thus  from  ±mP, 
by  multiplying  the  orthodiagonal  by  any  number  n,  a  series 
of  orthopyramids  rtraP/*,  is  produced  with  the  orthodomes 
±raPoo ,  as  limiting  forms.  The  clinodiagonal  produces  a 
similar  series,  distinguished  from  the  former  by  the  sign 
being  put  in  brackets,  thus,  db(wPw),  with  the  limiting 
clinodome  ( mP<x> )  always  completely  formed,  and  therefore 
without  the  signs  ±  attached.  From  o>P  arise  ortho- 
prisms  oo Ptt,  and  the  orthopinacoid  ooPoo;  and  clino- 
prisms  (ooPtt),  and  the  clinopinacoid  (ooPoo). 

The  combinations  of  this  system  may  be  easily  under- 
stood from  their  resemblance  to  those  of  the  rhombic ;  the 
chief  difficulty  being  in  the  occurrence  of  partial  forms, 
which,  however,  closely  resemble  the  hemihedric  forms  of 
the  previous  systems.  We  shall  therefore  only  select  a  few 
examples  frequently  observed  in  the  mineral  kingdom. 
Fig.  59  represents  a  very  common  form  of  gypsum  crystals 


Fig.  59.  Fig.  60. 

(ooPoo)  (P)  .  ooP(/)  .  P(&).    The  most  common  form  of 
augite  is  represented  in  fig.  60,  with  the  sign  ct>P(m)  . 


52 


A  POPULAR  TREATISE  ON  GEMS. 


oo  Poo  (r)  .  ( ooPoo )  (I)  .  P(s).  Fig.  61  is  a  crystal  of  com 
mon  felspar  or  orthoclase,  composed  of  the  clinopinacoid 
(ooPoo)  (Jf),  the  prism  ooP(fT),  the  basal  pinacoid  OP 
(P),  and  the  hemidomes  2P<x>  (y) :  to  which,  in  fig.  62  of 


Fig.  61. 


Fig.  62. 


the  same  mineral,  the  hemipyramid  P(o),  and  the  clino- 
dome  ( 2Poo )  (rc),  are  added. 

VI.  Tridinohedric  System. — This  is  the  least  regular  of 
all  the  systems,  and  departs  the  most  widely  from  symmetry 
of  form.  The  axes  are  all  unequal,  and  inclined  at  angles 
none  of  which  are  right  angles,  so  that  to  determine  any 
crystal  or  series  of  forms  the  proportion  of  the  axes  a :  b :  c, 
and  also  their  angles,  or  those  of  the  inclination  of  the  chief 
sections,  must  be  known.  As  in  the  previous  system,  one 
axis  is  chosen  as  the  principal  axis,  and  the  two  others  dis- 
tinguished as  the  macrodiagonal  and  brachydiagonal  axes. 
In  consequence  of  the  oblique  position  of  the  principal  sec- 
tions, this  system  consists  entirely  of  partial  forms  wholly 
independent  on  each  other,  and  each  composed  only  of  two 
parallel  faces.  The  complete  pyramid  is  thus  broken  up 
into  four  distinct  quarter  pyramids,  and  the  prism  into  two 
hemiprisms.  Each  of  these  partial  forms  is  thus  nothing 
more  than  a  pair  of  parallel  planes,  and  the  various  forms 
consequently  mere  individual  faces.  This  circumstance 


FORM    OF   MINERALS. 


53 


renders  many  triclinohedric  crystals  very  unsymmetrical  in 
appearance. 

Triclinohedric  pyramids  (fig.  63) 
are  bounded  by  eight  triangles,  whose 
lateral  edges  lie  in  one  plane.  They 
are  equal  and  parallel  two  and  two 
to  each  other ;  each  pair  forming,  as 
just  stated,  a  tetartopyramid  or  open 
form,  only  limited  by  combination 
with  other  forms,  or,  as  we  may  sup- 
pose, by  the  chief  sections.  The 
prisms  are  again  either  vertical  or  in- 
clined ;  the  latter  named  domes,  and 
their  section  is  always  rhomboidal.  In  deriving  the  forms, 
the  fundamental  pyramid  is  placed  upright  with  its  brachy- 
diagonal  axis  to  the  spectator,  and  the  .partial  forms  desig- 
nated, the  two  upper  by  'P  and  P',  the  two  lower  by  ,P 
and  Py,  as  hi  the  figure.  The  further  derivation  now  follows 
as  in  the  rhombic  system,  with  the  modifications  already 
mentioned,  so  that  we  need  not  delay  on  it  longer,  especially 
as  the  minerals  crystallizing  in  these  forms  are  not  numerous. 


Fig.  63. 


Fig.  64 

Some  combinations  of  this  system,  as  the  series  exhibited 
by  most  of  the  felspars,  approach  very  near  to  the  mono- 
clinohedric  system ;  while  others,  as  the  blue  copper,  01 


A   POPULAR   TREATISE    ON    GEMS. 


vitiiol,  and  axinite,  show  great  incompleteness  and  want  of 
symmetry.  In  the  latter  case  the  determination  of  the 
forms  is  often  difficult  and  requires  great  attention.  As 
specimens,  we  may  notice  the  albite  crystal  (fig.  64),  in 
which  P  is  the  basal  piuacoid  OP;  J/the  brachydiagonal 
pinacoid  ooPco;  s  the  upper  right  pyramid  P';  Zthe  right 
hemiprism  ooP';  T  the  left  hemiprism  oo'P;  and  x  the 
hemidome  'P'oo .  Figures  65  and  66  are  crystals  of  axinite, 


Fig.  65. 


Fig.  6G. 


the  former  from  Dauphine,  the  latter  very  common  in  Corn- 
wall, of  whose  faces  the  following  is  the  development : — r 
the  macropinacoid  ooPoo ;  P  the  left  hemiprism  co'P;  u 
the  left  upper  quarter  pyramid  'P ;  I  the  left  upper  quarter 
pyramid  2'P;  s  the  left  upper  partial  form  of  the  macro- 
pyramid  3'P3  ;  and  x  the  hemidome  2'P,oo  . 

Imperfections  of  Crystals. 

In  the  foregoing  description  of  the  forms  of  crystals  the 
planes  have  been  supposed  smooth  and  even,  the  faces 
equal  and  uniform,  or  at  the  same  distance  from  the  centre 
or  point  of  intersection  of  the  axes,  and  each  crystal  also 
perfect  or  fully  formed  and  complete  on  every  side.  In 
nature,  however,  these  conditions  are  rarely  if  ever  real- 
ized, and  the  edges  of  crystals  are  seldom  straight  lines,  or 
the  faces  mathematical  plane  surfaces.  A  very  interesting 
variety  of  these  irregularities,  which  pervades  all  the  sys- 
tems except  the  tesseral,  is  named  hemimorphism.  In  this 


FORM   OP   MIXEEALS. 


55 


the  crystals  are  bounded  on  the  opposite  ends  of  their  chiet 
axis  by  faces  belonging  to  distinct  forms,  and  hence  only 
the  upper  or  under  half  of  each  form  is  produced,  or  the 
crystal,  as  the  name  implies,  is  half-formed.  Figure  67  rep- 
resents a  common  variety  of  tourmaline,  bounded  on  the 


Fig.  67. 


Fig.  63. 


upper  end  by  the  planes  of  the  rhombohedrons  R  and— 2R, 
and  on  the  lower  end  by  the  basal  piuacoid.  In  fig.  68  of 
electric  calamine  the  upper  extremity  shows  the  basis  &, 
two  brachydomes  o  and  p,  and  two  macrodomes  m  and  l\ 
while  on  the  lower  end  it  is  bounded  by  ;the  faces  P  of  the 
primary  form.  This  appearance  becomes  more  interesting 
from  the  fact  that  most  hemimorphic  crystals  acquire  polar 
electricity  from  heat, — that  is,  exhibit  opposite  kinds  of 
electricity  at  opposite  ends  of  the  crystal. 

The  faces  of  crystals  are  very  frequently  rendered  im- 
perfect by  striae,  or  minute  linear  and  parallel  elevations 
and  depressions.  These  arise  in  the  oscillatory  combination 
of  two  crystal  forms,  alternately  prevailing  through  small 
spaces.  The  striae,  therefore,  are  in  reality  the  edges  of 
combined  forms.  They  are  very  common  on  quartz,  shorl, 
and  some  other  minerals ;  and  frequently  indicate  combina- 
tions where  only  a  simple  form  would  otherwise  appear  to 
exist.  The  cubes  and  pentagonal  dodecahedrons  of  iron 


56  A  POPULAR  TREATISE  ON  GEMS. 

pyrites  are  frequently  striated,  and  in  three  directions  at 
right  angles  to  each  other.  In  calc-spar  the  faces  of  the 
rhombohedron,— JR  (g  in  fig.  43  above)  are  almost  never 
without  striae  parallel  to  the  oblique  diagonal.  The  stria- 
tion  is  said  to  be  simple  when  only  one  series  of  parallel 
lines  appears  on  each  face,  or  feathered  when  two  systems 
diverge  from  a  common  line.  In  other  crystals  the  faces, 
then  said  to  be  drusy,  are  covered  by  numerous  projecting 
angles  of  smaller  crystals;  an  imperfection  often  seen  in 
fluor  spar.  The  faces  of  crystals  occasionally  appear  curved 
either,  as  in  tourmaline  and  beryl,  from  the  peculiar  oscil- 
latory combination  mentioned,  or  by  the  union  of  several 
crystals  at  obtuse  angles,  like  stones  in  a  vault,  as  in  stilbite 
and  prehnite.  A  true  curvature  of  the  faces  probably  oc- 
curs in  the  saddle-shaped  rhombohedrons  of  brown  spar 
and  siderite,  in  the  lens-like  crystals  of  gypsum,  and  in  the 
curved  faces  so  common  on  diamond  crystals.  In  chabasite 
similar  curved  faces  occur,  but  concave.  In  galena  and 
augite  the  crystals  are  often  rounded  on  the  corners,  as  if  by 
an  incipient  state  effusion.  On  other  crystals  the  faces  are 
rendered  uneven  from  inequalities  following  no  certain  rule. 
These  imperfections  furnish  valuable  assistance  in  develop- 
ing very  complex  combinations,  all  the  faces  of  each  indi- 
vidual form  being  distinguished  by  the  same  peculiarity  of 
surface. 

Irregularities  in  the  forms  of  crystals  are  produced  when 
the  corresponding  faces  are  placed  at  unequal  distances 
from  the  centre,  and  consequently  differ  in  form  and  size. 
Thus  the  cubes  and  octahedrons  of  iron  pyrites,  galena,  and 
fluor  spar,  are  often  lengthened  along  one  axis.  Quartz  is 
subject  to  many  such  irregularities,  which  are  seen  in  a  very 
remarkable  manner  on  the  beautiful  transparent  and  sharply 
angular  crystals  from  Dauphine.  In  such  irregular  forms, 
instead  of  one  line,  the  axes  are  then  represented  by  an 


FOKM    OF    MINERALS.  57 

infinite  number  of  lines,  parallel  to  the  ideal  axis  of  the 
figure.  The  same  irregularity  carried  to  a  greater  extent 
frequently  causes  certain  faces  required  for  the  symmetry 
of  the  form,  altogether  to  disappear.  Again,  some  crystals 
do  not  fill  the  space  marked  out  by  their  outline,  holes  and 
vacancies  being  left  in  the  faces,  occasionally  to  such  an 
extent  that  they  seem  little  more  than  mere  skeletons. 
This  appearance  is  very  common  on  crystals  produced  ar- 
tificially, as  in  common  salt,  alum,  bismuth,  silver,  &c.  A 
perfect  crystal  can  only  be  produced  when,  during  its  for- 
mation, it  is  completely  isolated,  so  as  to  have  full  room  to 
expand  on  every  side.  Hence  the  most  perfect  crystals 
have  been  originally  imbedded  singly  in  some  uniform  rock 
mass.  Next  to  them  in  perfection  are  forms  that  grow 
singly,  on  the  surface  of  some  mass  of  similar  or  distinct 
composition,  especially  when  the  point  of  adherence  is 
small.  An  incompleteness  of  form,  or  at  least  a  difficulty 
in  determining  it,  arises  from  the  minuteness  of  some  crys- 
tals, or  from  their  contracted  dimensions  in  certain  direc- 
tions. Thus  some  appear  mere  tabular  or  lamellar  planes, 
while  others  run  out  into  acicular,  needle-shaped,  or  capil- 
lary crystals.  Amid  all  these  modifications  of  the  general 
form  of  the  crystal,  of  the  condition  and  aspect  of  its  indi- 
vidual faces,  or  of  its  linear  dimensions,  one  important  ele- 
ment, the  angular  measurement,  remains  constant.  In  some 
monoaxial  crystals,  indeed,  increase  of  temperature  produces 
an  unequal  expansion  in  different  directions,  slightly  chang- 
ing the  relative  inclination  of  the  faces,  but  so  small  as  to 
be  scarcely  perceptible  in  common  measurements,  and  hence 
producing  no  ambiguity.  More  important  are  the  angular 
changes  which  in  many  species  accompany  slight  changes 
in  chemical  composition,  particularly  in  the  relative  propor- 
tions of  certain  isomorphous  elements.  But  notwithstand- 
ing these  limitations,  the  great  truth  of  the  permanence  of 


58 


A  POPULAR  TREATISE  ON  GEMS. 


the  angular  dimensions  of  crystals,  announced  by  Rome  de 
1'Isle,  remains  unaffected;  only,  as  Mohs  well  states,  it 
must  not  be  interpreted  with  a  rigid  immutability,  incon- 
sistent with  the  whole  analogy  of  other  parts  of  nature. 


The  Goniometer  and  Measurement  of  Crystals. 

The  fact  just  stated  of  the  permanence  of  the  angular  di- 
mensions of  crystals,  shows  the  importance  of  some  accurate 
method  of  measuring  their  angles  ;  that  is,  the  inclination 
of  two  faces  to  each  other. 
Two  instruments  have  been 
specially  used  for  this  pur- 
pose,— the  common  or  contact 
goniometer,  invented  by  Ca- 
ringeau,  and  the  reflecting  go- 
niometer of  Wollaston.  The 
former  is  simply  two  brass 
rulers  turning  on  a  common 
centre,  between  which  the 
crystal  is  so  placed  that  its 
faces  coincide  with  the  edges 
of  the  rulers,  and  the  angle  is 
then  measured  on  a  graduated 
arc.  This  instrument  is  suffi- 
ciently accurate  for  many  pur- 
poses and  for  large  crystals ; 
but  for  precise  determination 
is  far  inferior  to  the  reflecting 
goniometer.  This  requires 
smooth  and  even  faces,  but 

Fig.  69. 

these  may  be  very  small,  even 

the  hundredth  of  an  inch,  in  skilful  hands ;  and  as  small 

crystals  are  generally  most  perfect,  far  greater  accuracy  can 


FORM    OF    MINERALS.  59 

be  attained,  and  the  measurement  depended  on  to  one 
minute  (!'). 

The  reflecting  goniometer  is  represented  in  fig.  69.  It 
consists  essentially  of  a  graduated  circle  mm,  divided  on  its 
edge  into  twice  180°,  or  more  often  into  half  degrees,  the 
minutes  being  read  off  by  the  vernier  hh.  This  circle  turns 
on  an  axis  connected  with  ft,  so  that  by  turning  this  the 
circle  is  moved  round,  but  is  stopped  at  1 80°,  when  moving 
in  one  direction,  by  a  spring  at  k.  The  other  part  of  the 
instrument  is  intended  to  attach  and  adjust  the  crystal  to 
be  measured.  The  first  axis  of  mm  is  hollow,  and  a  second 
axis,  ««,  passes  through  it  from  ss,  so  that  this  and  all  the 
connected  parts  from  b  tof  can  be  turned  without  moving 
the  circle  mm.  The  axis  d  passes  through  a  hole  in  be,  so 
that  it  can  turn  the  arm  de  into  any  required  position ;  f  is 
a  similar  axis  turning  the  arm  og ;  and  pq  a  fourth  axis,  in 
like  manner  movable  in  g,  and  with  a  small  knob  at  q,  to 
which  the  crystal  to  be  measured  is  attached. 

When  about  to  use  the  instrument,  it  should  be  placed 
on  a  table,  with  its  base  horizontal,  which  is  readily  done 
by  the  screws  in  it,  and  opposite  to  a  window  at  about  12 
or  15  feet  distance,  so  that  its  axis  shall  be  parallel  to  the 
horizontal  bars  of  the  window.  One  of  the  upper  bars  of 
the  window,  and  also  the  lower  bar,  or,  instead  of  the  lat- 
ter, a  white  line  on  the  floor  or  table  parallel  to  the  window, 
should  then  be  chosen  in  order  to  adjust  the  crystal.  The 
observer  places  himself  behind  the  instrument  with  the  side 
a  at  his  right  hand.  The  crystal  is  then  attached  to  q  by 
a  piece  of  wax,  with  the  two  faces  to  be  measured  upward. 
The  axis  fo  is  made  parallel  to  o#,  and  the  eye  being 
brought  near  to  the  first  face  of  the  crystal,  the  axes  aa 
and  p  are  turned  till  the  image  of  the  window  is  seen  re- 
flected in  the  face  with  the  horizontal  and  vertical  bars  in 
their  position.  The  axis  d  is  then  turned  through  a  con- 


60  A  POPULAR  TREATISE  ON  GEMS. 

siderable  angle  (say  60°),  and  the  image  of  the  window 
again  sought  and  brought  into  its  proper  place  by  turning 
the  axis/",  without  moving  p.  When  this  is  done,  that  face 
is  brought  into  its  true  position,  normal  to  d,  so  that  no 
motion  of  d  can  disarrange  it.  Hence  the  image  of  the 
window  may  now  be  sought  in  the  second  face  and  brought 
into  its  true  position,  with  the  horizontal  bars  seen  horizon- 
tal, by  moving  the  axes  d  and  a.  When  this  is  done  the 
crystal  is  properly  adjusted,  and  the  angle  is  thus  measured. 
First  bring  the  zero  of  the  circle  and  vernier  to  coincide, 
and  then  turn  the  inner  axis  a  or  as,  and  move  the  eye  till 
the  image  of  the  upper  bar  of  the  window  reflected  from 
the  more  distant  face  of  the  crystal  coincides  with  the  lower 
bar  or  horizontal  line  seen  directly.  Keeping  the  eye  in 
its  place,  turn  the  outer  axis  tt  till  the  reflected  image  of 
the  upper  bar  in  the  other  face  in  like  manner  coincides 
with  the  lower  line,  and  the  angle  of  the  two  faces  is  then 
read  off  on  the  divided  circle.  As  the  angle  measured  is 
not  directly  that  of  the  faces,  but  of  the  rays  of  light  re- 
flected from  them,  or  the  difference  of  the  angle  wanted 
from  180°,  the  circle  has  the  degrees  numbered  in  the  re- 
verse direction,  so  as  to  give  the  angle  without  the  trouble 
of  subtracting  the  one  from  the  other. 

The  above  apparatus  for  adjusting  the  crystal  is  an  im- 
provement suggested  by  Naumann.  In  the  original  instru- 
ment the  axis  fo  was  made  to  push  in  or  out  in  a  sheath, 
and  had  a  small  brass  plate,  bent  at  right  angles,  inserted 
in  a  cleft  at  o,  to  which  the  crystal  was  attached.  The  crys- 
tal was  adjusted,  as  formerly,  by  moving  the  plate,  or  the 
axis/b,  and  by  slight  motion  of  the  arm  de,  which  should 
be  at  right  angles  nearly  to  be  when  used.  A  considerable 
improvement  is,  to  have  a  small  mirror  fixed  on  the  stand 
below  the  crystal,  with  its  face  parallel  to  the  axis  aa,  and 
inclined  at  45°  to  the  window,  when  the  lower  line  can  be 


FORM    OF   MINERALS.  61 

dispensed  with,  and  the  instrument  used  for  various  other 
purposes  of  angular  measurement.  Many  alterations  have 
been  suggested  for  the  purpose  of  insuring  greater  accuracy, 
but  the  simple  instrument  is  sufficient  for  all  purposes  of  de- 
terminative mineralogy,  and  the  error  from  the  instrument 
will  in  most  cases  be  less  than  the  actual  variations  in  the 
dimensions  of  the  crystals.  Greater  simplicity  is  indeed 
rather  desirable,  and  the  student  will  often  find  it  sufficient 
to  attach  the  crystal  by  a  piece  of  wax  to  the  axis  a  directly, 
and  give  it  the  further  adjustment  by  the  hand.  The  only 
use  of  the  parts  from  b  to  q  is  to  enable  the  observer  to 
place  the  crystal  properly ;  that  is,  with  the  edge  to  be 
measured  parallel  to  the  axis  of  the  instrument,  and  as 
nearly  as  possible  coinciding  with  its  centre.  This  is 
effected  when  the  reflection  of  the  horizontal  bar  in  the 
two  faces  appears  parallel  to  that  edge. 

Modes  or  Twin  Crystals. 

When  two  similar  crystals  of  a  mineral  species  are  united 
with  their  similar  faces  and  axes  parallel,  the  one  forms 
merely  a  continuation  or  enlargement  of  the  other,  and 
every  crystal  may  be  regarded  as  thus  built  up  of  a  num- 
ber of  smaller  crystals.  Frequently,  however,  crystals  are 
united  according  to  precise  laws,  though  all  their  similar 
faces  and  axes  are  not  parallel,  and  then  are  named  macles 
or  twin  crystals.  In  one  class  of  macles  the  axes  of  the 
two  crystals  are  parallel,  and  in  another  they  are  inclined. 
The  former  only  occur  among  hemihedric  forms,  and  the 
two  crystals  are  then  combined  in  the  exact  position  in 
which  they  would  be  derived  from  or  reproduce  the  pri- 
mary holohedric  form.  The  second  class,  with  oblique 
axes,  occur  both  in  holohedric  and  hemihedric  forms,  and 
the  two  individuals  are  placed  in  perfect  symmetry  to  each 


62  A   POPULAR  TREATISE    ON   GEMS. 

other,  in  reference  to  a  particular  face  of  the  crystal  which 
forms  the  plane  of  union,  or  the  equator  of  the  made.  We 
may  also  suppose  the  two  crystals  originally  parallel,  and 
the  one  turned  round  the  normal  of  the  united  faces  by  180° 
(often  90°  or  60°),  while  the  other  is  stationary.  Or  we 
may  suppose  a  crystal  cut  into  halves  in  a  particular  direc- 
tion, and  one  half  turned  1 80°  on  the  other ;  and  hence  the 
name  of  hemitrope  given  to  them  by  Hauy.  The  position 
of  the  two  individuals  in  this  case  corresponds  with  that  of 
an  object  and  its  image  in  a  mirror,  whose  surface  then 
represents  the  plane  of  union. 

The  manner  in  which  the  crystals  unite  also  differs. 
Some  are  merely  opposed  or  in  simple  contact ;  others  are, 
as  it  were,  grown  together,  and  mutually  interpenetrate, 
occasionally  so  completely  as  to  appear  like  one  individual. 
The  twin  edges  and  angles  in  which  the  two  unite  are  often 
re-entering ;  or  they  may  coincide  in  one  plane,  when  the 
line  of  union  is  either  imperceptible,  or  is  only  marked  by 
the  meeting  of  two  systems  of  striae,  or  other  diversity  in 
the  physical  characters  of  the  two  faces. 

The  formation  of  twin  crystals  may  be  again  repeated, 
forming  groups  of  three,  four,  or  more.  When  the  faces  of 
union  are  parallel  to  each  other,  the  crystals  form  rows  of 
indeterminate  extent;  where  they  are  not  parallel,  they 
may  return  into  each  other  in  circles,  or  form  bouquet-like 
or  other  groups.  Where  crystals  are  merely  in  juxtaposi- 
tion, they  are  sometimes  much  shortened  in  the  direction 
of  the  twin  axis ;  and  where  many  occur  in  a  series  with 
parallel  position,  are  often  compressed  into  very  thin  plates, 
frequently  not  thicker  than  paper,  giving  to  the  surface  of 
the  aggregate  a  peculiar  striated  aspect. 

Only  a  few  twin  crystals  in  the  different  systems  can  be 
noticed,  chiefly  as  examples  of  this  mode  of  formation.  In 
the  tesseral  system,  forms  that  unite  with  parallel  axes  pro- 


F011M    OF    MINERALS. 


63 


duce  intersecting  macles  like  the  pentagonal  dodecahedrons 
of  iron  pyrites  in  fig.  70,  and  the  tetrahedrons  of  gray-cop- 


Fig.  70. 


Fig.  71. 


per  or  fhhlore  in  fig.  71,  a  similar  formation  also  occurring  ' 
in  the  diamond.  In  macles  with  inclined  axes  the  two 
forms  almost  always  unite  by  a  face  of  the  octahedron,  and 
the  two  individuals  are  then  generally  apposed  and  short- 
ened in  the  direction  of  the  twin  axis  by  one  half,  so  that 
they  appear  like  a  crystal  that  has  been  divided  by  a  plane 
parallel  to  one  of  its  faces,  and  the  two  halves  turned  round 
on  each  other  by  an  angle  of  180°.  In  this  manner  two 
octahedrons  of  the  spinel,  magnetic  iron  ore,  or  automolite 


Fig.  72. 


Fig.  73. 


(fig.  72),  are  frequently  united.     The  same  law  prevails  in 
the  intersecting  cubes  of  fluor  spar,  iron  pyrites,  and  galena, 


64 


A  POPULAR  TREATISE  ON  GEMS. 


represented  in  fig.  73.     In  fig.  74  of  zinc-blende,  two  rhom- 
bic dodecahedrons  are  united  by  a  face  of  the  octahedron. 
In  the  Tetragonal  system,  twin  crystals  with  parallel  axes 


Fig.  74. 


Fig.  75. 


rarely  occur,  but  are  seen  in  chalcopyrite,  and  one  or  two 
other  minerals.  Where  the  axes  are  inclined  the  plane  of 
union  is  very  often  one  of  the  faces  of  the  pyramid  Poo ,  or 
one  of  those  faces  that  would  regularly  replace  the  polar 
edges  of  the  fundamental  form  P.  The  crystals  of  tin  ore 
obey  this  law,  as  seen  in  fig.  75,  where  the  individuals  are 
pyramidal,  and  in  the  knee-shaped  crystal  (fig.  76),  where 


Fig.  76. 


Fig.  77. 


they  are  more  prismatic.  Hausmanite  appears  like  fig.  77, 
in  which  the  fundamental  pyramid  P  prevails,  on  whose  polar 
edges  other  crystals  are  often  very  symmetrically  repeated. 


FORM    OF    MINERALS. 


65 


a  central  individual  appearing  like  the  support  of  all  the 
others.     Almost  identical  forms  occur  in  chalcopyrite. 

In  the  Hexagonal  system,  twin  crystals  with  parallel  axes 
are  common,  as  in  calc-spar,  chabasite,  hematite,  and  other 
rhombohedric  minerals.  In  calc-spar  they  often  form  very 
regular  crystals,  the  two  individuals  uniting  by  a  plane 
parallel  to  the  base,  so  as  to  appear  like  a  single  crystal,  as 
in  fig.  78,  where  each  end  shows  the  forms  ooR.  —  £  R,  but 
in  a  complementary  position ;  or  in  fig.  79  of  two  scaleno- 
hedrons  R3  from  Derbyshire.  The  rhombohedric  crystals 
of  chabasite  often  appear  intersecting  each  other,  like  those 
of  fluor  spar  in  fig.  73.  The  purer  varieties  of  quartz  or 


Fig.  78. 


Fig.  79. 


Fig.  80. 


rock  crystal,  in  consequence  of  the  tetartohedric  character 
of  its  crystallization,  often  exhibit  twins.  In  these  the 
pyramid  P  separates  into  two  rhombohedrons  P  and  z, 
which,  though  geometrically  similar,  are  yet  physically 
distinct.  In  fig.  80  the  two  individuals  are  only  grown  to- 
gether, but  more  commonly  they  penetrate  each  other  in 
an  irregular  manner,  forming  apparently  a  single  crystal. 
Twins  with  oblique  axes  are  also  common,  the  plane  of 
union  being  usually  one  face  of  the  rhombohedron.  Thus 
in  calc-spar  two  rhombohedrons  are  often  joined  by  a  face 


66 


A  POPULAR  TREATISE  ON  GEMS. 


of— gll,  the  two  axes  forming  an  angle  of  127°  34';  occa- 
sionally a  third  individual  is  interposed  in  a  lamellar  form, 
as  in  fig.  81,  when  the  two  outer  crystals  become  parallel. 


Fig.  81. 


Fig.  82. 


This  latter  arrangement  is  very  common  in  the  highly 
cleavable  varieties  of  Iceland  spar.  When  the  crystals 
unite  in  a  face  of  the  rhombohedron  R,  fig.  82,  they  form 
an  angle  of  89°  8',  differing  little  from  a  right  angle,  by 
which  the  occurrence  of  this  law  is  very  easily  recognized, 
especially  in  prismatic  varieties. 

In  the  rhombic  system,  twin  crystals  with  parallel  axes 
are  very  rare,  but  those  with  oblique  axes  common,  the 
plane  of  union  being  one  of  the  faces  of  the  prism  GO  P. 
Twins  of  this  kind  are  very  distinctly  seen  in  arragonite, 


Fig.  S3.  Fig.  84  Fig.  85. 

carbonate  of  lead,  marcasite,  stephanite,  mispickel,   and 
other  minerals.     In  arragonite  the  crystals  partly  interpen- 


FORM    OF    MINERALS. 


6-7 


etrate,  partly  are  in  mere  juxtaposition,  as  in  fig.  83,  where 
the  individuals  are  formed  by  the  Combination  ooP(Jlf)  . 
oo  Poo  (A),  Poo  (&),  and  in  figure  84  where  several  crystals 
of  the  same  combination  form  a  series  with  parallel  planes 
of  union  ;  the  inner  members  being  so  shortened  that  they 
appear  like  mere  lamellar  plates  producing  striae  on  the 
faces  Poo  and  ooPoo  of  the  made.  In  fig.  85  four  crystals, 
each  of  the  combination  ooP  .  2Poo ,  having  united  in  in- 
clined planes,  form  a  circular  group,  returning  into  itself. 
The  carbonate  of  lead  often  occurs  in  macles  in  all  respects 


Fig.  86.  Fi?.  87. 

similar.     In  staurolite,  individuals  of  the  prismatic  combi- 

tion  oo P  .  oo  Poo  .  OP,  combine  either,  as  in  fig.  86,  by  a 

face  of  the  braehydome  |Poo ,  with  their 

chief  axes  almost  at  right  angles;  or,  as  in 

fig.  87,  by  a  face  of  th»  brachypyramid 

f  P|,  the  chief  axes  and  the  brachypina- 

coids  (o)  of  the  two  single  crystals  meeting 

at  an  angle  of  about  60°.     Finally,  in  fig. 

88,  two  harmotome  crystals  of  the  most 

common  combination    ooPoo  .  ooPoo  .  P  . 

Poo  ,  intersect  each  other  so  nearly  at  right 

angles,  that  their  principal  axes  seem  to  Fig.88. 

coincide,  and  the  brachypiuacoid  (q)  of  the  one  crystal 


68 


A  POPULAR  TREATISE  ON  GEMS. 


(with  a  rhombic  striae)  is  parallel  to  the  macropinacoid  (q) 
of  the  other. 

In  -the  monoclinohedric  system  the  most  common  macles 
are  those  in  which  the  principal  axes  and  the  chief  sections 
of  the  two  crystals  are  parallel  to  each  other,  and  conse- 
quently the  principal  axis  is  also  the  twin  axis.  Usually 
the  two  individuals  are  united  by  a  face  parallel  to  the  or- 
thodiagonal  chief  section,  as  in  figure  89  of  gypsum,  where 
two  crystals  of  the  combination  (ooPco).ooP.— P,  shown 
in  fig.  59,  unite  so  regularly  that  the  faces  of  the  pinacoids 
(P  and  P')  form  only  one  plane.  In  a  similar  manner  the 
augite  crystals  of  the  combination  ooP.  ooPoo  .  (ooPoo). 
P,  represented  singly  in  fig.  60,  are  in  fig.  90  united  in  a 


Fig.  89. 


Fig.  90. 


Fig.  91. 


macle  so  very  symmetrical  and  regular  that  the  line  of 
junction  cannot  be  observed  on  tlie  face  of  the  clinopinacoid. 
The  two  hemipyramids  P  (s)  (like  —  P  (I)  in  the  gypsum 
crystal  above)  form  on  one  side  a  re-entering,  on  the  other 
a  salient  angle.  Hornblende,  wolfram,  and  other  minerals 
exhibit  a  similar  appearance.  In  other  cases  the  individuals 
partially  penetrate  each  other,  being,  as  it  were,  crushed 
together  in  the  direction  of  the  orthodiagonal.  This  mode 
of  union  is  not  uncommon  in  gypsum,  and  very  frequent  in 
orthoclase  felspar.  Two  crystals  of  the  latter,  of  the  com- 


FOKM    OF    MINERALS. 


69 


bination  ( ooPoo )  .  ooP  .  OP  .  2Poo ,  as  in  fig.  61  above,  are 
often  pushed  sidewise  into  each  other,  as  shown  in  fig.  91. 

In  the  triclinohedric  system,  some  twin  formations  are  of 
great  importance  as  a  means  of  distinguishing  the  triclino- 
hedric from  the  monoclinohedric  species  of  felspar.  In  one 
variety  the  twin  axis  is  the  normal  to  the  brachydiagonal 
chief  section.  But  in  the  triclinohedric  felspars  this  sec- 
tion is  not,  as  it  is  in  the  monoclinohedric  species,  perpen- 
dicular to  the  basis,  and  consequently  the  two  bases  form 
on  one  side  a  re-entering,  on  the  other  a  salient  angle ; 
whereas  in  the  monoclinohedric  felspars  (where  the  brachy- 
diagonal chief  section  corresponds  to  the  clinodiagonal),  no 
twin  crystals  can  be  produced  in  conformity  to  this  law,  and 
the  two  bases  fah1  in  one  plane.  The  albite  and  oligoclase 
very  often  exhibit  such  twins,  as  in  figure  92,  where  the 


Fig.  92. 


very  obtuse  angles  formed  by  the  faces  of  OP,  or  P  and  P' 
(as  well  as  those  of  'P'oo  ,  or  x  and  #'),  are  a  very  charac- 
teristic appearance,  marking  out  this  mineral  at  once  as  a 
triclinohedric  species.  Usually  the  twin  formation  is  re- 
peated, three  or  more  crystals  being  combined,  when  those 
in  the  centre  are  reduced  to  mere  plates.  When  very  nu- 
merous, the  surfaces  P  and  x  are  covered  with  fine  striae, 
often  only  perceptible  with  a  microscope.  A  second  law 


A  POPULAR  TREATISE  ON  GEMS. 


Fig.  93. 


observed  in  triclinohedric  felspars,  particularly  the  albite 
and  labradorite,  is  that  the  twin  axis  corresponds  with  that 
normal  of  the  brachydiagonal  which  is 
situated  in  the  plane  of  the  base.  In 
pericline,  a  variety  of  albite,  these  twins 
appear  as  in  fig.  93,  where  the  two  crys- 
tals are  united  by  a  face  of  the  basal 
pinacoid  P,  while  the  faces  of  the  two 
brachypinacoids  (Jffand  M')  form  edges 
with  very  obtuse  angles  (1*73°  22'),  re- 
entering  on  the  one  side  and  salient  on 
the  other.  These  edges,  or  the  line  of 
junction  between  JbTand  Jtf'9  are  also  parallel  to  the  edges 
formed  by  these  faces  and  the  base,  or  those  between  M 
and  P.  In  this  case  also  the  macles  are  occasionally  sev- 
eral times  repeated  when  the  faces  appear  covered  with  fine 
stria3. 

Irregular  Aggregation  of  Crystals. 

Besides  the  regular  unions  now  described,  crystals  are 
often  aggregated  in  peculiar  ways,  to  which  no  fixed  law 
can  be  assigned.  Thus  some  crystals,  apparently  simple, 
are  composed  of  concentric  crusts  or  shells,  which  may  be 
removed  one  after  the  other,  always  leaving  a  smaller  crys- 
tal like  a  kernel,  with  smooth  distinct  faces.  Some  speci- 
mens of  quartz  from  Beeralston  in  Devonshire  consist  ap- 
parently of  hollow  hexagonal  pyramids  placed  one  within 
another.  Other  minerals,  as  fluor  spar,  apatite,  heavy  spar, 
and  calc-spar,  exhibited  a  similar  structure  by  bands  of  dif- 
ferent colors. 

Many  large  crystals,  again,  appear  like  an  aggregate  of 
numerous  small  crystals,  partly  of  the  same,  partly  of  dif- 
ferent forms.  Thus  some  octahedrons  of  fluor  spar  from 
Schlaggenwald  are  made  up  of  small  dark  violet-blue  cubes, 


FORM    OF   MINERALS.  71 

whose  projecting  angles  give  a  drusy  character  to  the  faces 
of  the  larger  form.  Such  polysynthetic  crystals,  as  they 
may  be  called,  are  very  common  in  calc-spar. 

A  similar,  but  still  more  remarkable  formation,  is  where 
two  crystals  of  distinct  species  are  conjoined.  Such  unions 
of  cyanite  and  staurolite  have  been  long  well  known,  and 
the  graphic-granite  exhibits  a  similar  union  between  large 
felspar  crystals  and  many  smaller  ones  of  mica  and  quartz. 

Forms  of  Crystalline  Aggregates. — Crystals  have  often 
been  produced  under  conditions  preventing  the  free  de- 
velopment of  their  forms.  They  then  compose  crystalline 
aggregates,  of  which  the  following  may  be  distinguished  : — 
Granular,  formed  of  grains,  generally  angular,  but  rarely 
rounded  or  flattened.  Lamellar  consist  of  broad  plates, 
which  are  tabular  when  of  uniform  thickness,  lenticular 
when  becoming  thinner  on  the  edges,  icedge-shaped  when 
sharpened  towards  one  edge,  and  scaly  when  the  plates  are 
very  small.  Columnar,  in  which  the  individuals  are  drawn 
out  in  one  direction  more  than  in  the  others ;  bacittary  or 
rod-like,  in  which  the  columns  are  of  uniform  thickness ; 
acicular  or  needle-shaped,, in  which  they  are  pointed;  and 
fibrous,  in  which  they  are  very  fine.  In  the  broad-colum- 
nar the  columns  are,  as  it  were,  compressed,  or  broader  in 
one  direction  than  the  other.  The  distinctions  of  large, 
coarse,  small,  or  fine-granular ;  thick  or  thin  scaly ;  straight, 
curved,  or  twisted- columnar ;  parallel,  diverging,  or  con- 
fused-fibrous ;  and  such  like,  are  easily  understood. 

Aggregates  which  have  been  able  to  crystallize,  at  least, 
with  a  certain  degree  of  freedom,  have  been  distinguished 
by  Mohs  into  crystal  groups  and  druses :  the  former  includ- 
ing all  unions  of  several  imbedded  crystals  ;  the  latter  those 
of  crystals  that  have  grown  together  on  a  common  support. 
In  the  groups,  crystals  with  their  faces  otherwise  perfect 
are  conjoined  in  various  ways.  Sometimes  they  radiate,  as 


72  A  POPULAR  TREATISE  ON  GEMS. 

it  were,  from  a  common  centre,  and  produce  spheroidal,  el- 
lipsoidal, or  other  forms,  frequent  in  gypsum,  iron  pyrites, 
and  other  minerals  imbedded  in  clay.  Where  many  such 
masses  are  united,  they  are  named  botryoidal  when  like 
bunches  of  grapes,  mammellated  where  the  spheres  are 
larger  and  less  distinct,  and  reniform  or  kidney-shaped 
where  the  masses  are  still  larger.  Some  groups  are  par- 
tially attached  by  a  small  point ;  but  the  mass  is  generally 
free. 

Crystals  are  often  grouped  in  rows  or  in  one  direction, 
forming,  when  they  are  very  small,  capillary  or  hair-like, 
and  filiform,  thread,  or  wire-like  forms,  which  are  common 
among  native  metals,  as  gold,  silver,  copper,  and  bismuth, 
in  silver  glance  and  a  few  other  materials.  Sometimes  the 
masses  are  dentiform,  consisting  of  portions  resembling 
teeth ;  as  is  very  common  in  silver.  Often  these  groups 
expand  in  several  directions,  and  produce  arborescent, 
dendritic,  foliated,  feathered,  or  other  forms,  very  common 
in  copper.  In  these  groups,  however,  a  certain  dependence 
on  the  crystallographic  character  of  the  species  may  be 
observed.  The  lamellar  minerals  often  form  fan-shaped, 
wheel-like,  almond-shaped,  comb-like,  or  other  groups. 
The  fibrous  types,  again,  are  disposed  in  parallel  or  diverg- 
ing bundles,  or  in  radiating,  stellar,  and  other  masses. 
Coralloidal  (like  coral),  fruticose  (like  cauliflower),  and  other 
forms,  have  also  been  observed. 

In  druses,  many  crystals  rise  side  by  side  from  a  common 
support ;  sometimes  only  the  granular  mass  composed  of 
their  united  bases,  at  other  times  some  distinct  body.  The 
form  of  a  druse  is  determined  by  that  of  the  surface  on 
which  it  grows,  and  consequently  is  often  very  irregular  or 
wholly  accidental.  Where  completely  inclosed  they  have 
been  named  drusy  cavities,  and  when  of  a  spheroidal  form, 
geodes.  A  drusy  crust,  again,  consists  of  a  thin  layer  of 


FORM   OF    MINERALS.  73 

small  crystals  investing  the  surface  of  a  large  crystal  or"  of 
some  othep  body. 

The  minute  or  cryptocrystalline  minerals  form  similar 
aggregates.  In  the  globular  or  the  oolitic,  the  minute  crys- 
tals often  appear  to  radiate  from  a  centre,  or  form  concen- 
tric crusts.  Somewhat -similar  are  the  stalactites  and  sta- 
lagmites, in  which  the  mineral,  especially  rock-salt,  lime- 
stone, chalcedony,  opal,  limonite,  has  been  deposited  from 
a  fluid  dropping  slowly  from  some  overhanging  body.  In 
this  case  the  principal  axis  of  the  figure,  generally  a  hollow 
tube,  is  vertical,  while  the  individual  parts  are  arranged  at 
right  angles  to  this  direction.  In  other  cases  the  mineral 
has.  apparently  been  deposited  from  a  fluid  mass  moving 
slowly  in  a  particular  direction,  which  may  be  regarded  as 
the  chief  axis-  of  the  figure,  while  the  axes  of  the  indi- 
vidual crystals  may  assume  a  different  position. 

By  far  the  largest  masses  of  the  mineral  kingdom  have, 
however,  been  produced  under  conditions  in  which  a  free 
development  of  their  forms  was  excluded.  This  has  been 
the  case  with  the  greater  portion  of  the  minerals  compos- 
ing rocks  or  filling  veins  and  dykes.  The  structure  of  these 
masses  on  the  large  scale  belongs  to  geology,  but  some 
varieties  of  the  texture  visible  even  in  hand  specimens  may 
be  noticed.  The  individual  grains  or  masses  have  seldom 
any  regular  form,  but  appear  round,  long,  or  flat,  according 
.to  circumstances,  and  as  each  has  been  more  or  less  checked 
in  the  process  of  formation.  Even  then,  however,  a  cer- 
tain regularity  in  the  position  of  the  parts  is  often  observ- 
able, as  in  granite,  in  which  the  cleavage  planes,  and  con- 
sequently the  axes  of  the  felspar  crystals,  are  parallel. 
Where  these  grains  are  all  pretty  similar  in  size  and  shape, 
the  rock  is  named  massive  when  they  are  small,  or  granular 
when  they  are  larger  and  more  distinct.  Sometimes  the  rock 
becomes  slaty,  dividing  into  thin  plates ;  or  concretionary, 

4 


74  A    POPULAR    TREATISE    ON  'GEMS. 

forming  roundish  masses ;  at  other  times  the  interposition 
of  some  foreign  substance  (gas  or  vapor)  has  renderetl  it 
porous,  cellular  or  vesicular,  giving  rise  to  drusy  cavities. 
These  cavities  are  often  empty,  but  have  occasionally  been 
filled  by  other  minerals,  when  the  rock  is  named  amygda- 
loidal,  from  the  almond-like  shape  of  the  inclosed  masses. 

Many  of  the  above  external  forms  appear  also  in  the 
amorphous  solid  minerals,  in  which  no  trace  of  individual 
parts,  and  consequently  of  internal  structure,  is  observable. 
They  are  not  unfrequently.  disposed  in  parallel  or  concen- 
tric layers,  of  uniform  or  distinct  colors ;  and  may  assume 
spherical,  cylindrical,  stalactitic,  and  other  appearances. 

Pseudomorphism. — When  the  substance  of  one  mineral 
assumes  the  external  form  of  some  other  mineral,  it  is  named 
a.pseudomorph.  In  some  named  incrusting  pseudomorphs 
the  original  crystal  is  covered  by  a  rough  or  drusy  surface 
of  the  second  mineral,  frequently  not  thicker  than  paper. 
Occasionally  the  first  crystal  has  been  removed,  and  noth- 
ing but  the  shell  remains ;  or  the  cavity  has  been  filled  by 
a  distinct  mineral  species,  or  a  crystalloid,  as  it  may  .be 
named,  forming  an  exact  representation  of  the  original,  but 
of  a  different  substance. 

More  commonly  the  new  mineral  substance  has  gradually 
expelled  the  old,  and  replacing  it,  as  it  were,  atom  by  atom, 
has  assumed  its  exact  form.  In  other  cases  not  the  whole 
substance  of  the  original  crystal,  but  only  one  or  more  of 
its  elements,  has  been  changed,  or  the  whole  matter  has 
remained,  but  in  a  new  condition.  Thus  arragonite  crys- 
tals have  been  converted  into  calc-spar,  the  chemical  com- 
position of  both  being  identical ;  or  gaylussite  has  been 
changed  into  calc-spar,  andalusite  into  cyanite,  by  the  loss 
of  certain  elements.  On  the  other  hand,  anhydrite  be- 
comes gypsum,  red-copper .  ore  malachite,  by  addition  of 
new  matter.  Or-tho  elements  are  partially  changed,  as 


.    ••  FORM    OP   MINERALS.  75 

felspar  T-to  kaolin,  quartz  or  pearl  spar  into  talc,  iron  pyrites 
or  iron  glance  into  brown-iron  ore>  azurite  into  malachite, 
augite  into  green  earth.  The  true  nature  of  such  bodies  is 
shown  by  the  internal  structure,  having  no  relation  to  the 
external  form  or  apparent  system  of  crystallization. 

The  process  of  petrifaction  of  organic  bodies  is  in  reality 
a  species  of  pseud oinorphic  formation,  and  lias  been  pro- 
duced in  all  the  above  modes.  External  and  internal  casts 
of  organic  bodies  are  not  uncommon.  In  other  cases  the 
original  substance  has  been  replaced  by  some  mineral  which 
has  preserved  not  merely  the  external  form,  but  ev'en  the 
"minutest  detail  of  internal  structure ;  so  that  the  different 
kinds  of  wood  have  been  distinguished  in  their  silicified 
trunks.  The  most  common  petrifying  substances  are  silica 
and  carbonate  of  lime.  In  encrynites,  echinites,  belemnites, 
and  other  fossils,  the  crystals  of  calc-spar  often  occur  in 
very  regular  positions.  In  some  varieties  of  petrified  wood 
both  the  ligneous  structure  and  the  cleavage  of  the  calc- 
spar  are  observable. 

Different  from  the  above  are  mineralized  bodies,  in  which 
the  original  structure  is  still  retained,  but  their  chemical 
nature  partially  changed.  In  these  a  complete  series  may 
be  often  traced,  as  from  wood  or  peat,  through  the  varie- 
ties of  brown  coal,  common  coal,  anthracite,  and  graphite, 
perhaps  even  to  the  diamond. 


CHAPTER  II. 
PHYSICAL  PROPERTIES  OF  MINERALS. 

THE  physical  characters  of  minerals  comprehend, — 1st. 
Those  properties  derived  from  the  nature  of  the  substance 
itself,  as  coherence,  mode  of  fracturej  elasticity,  and  density 


7G  A    POPULAR    TREATISE    ON"    GEMS.     . 

or  specific  gravity ;  2cl  Those  phenomena  called  forth  in 
minerals  by  the  influence  of  some  external  power  or  agent, 
as  their  optical,  electric,  or  thermal  relations;  and,  3d. 
Other  characters  depending  on  the  personal  sensation  of 
the  observer — on  his  taste,  smell,  and  touch.  All  these 
properties  furnish  useful  characters  in  distinguishing  and 
describing  mineral  species.  • 

Cleavage  and  Fracture. 

In  many  species  there  are  certain  planes  at  right* angles 
to  which  cohesion  seems  to  be  at  a  minimum,  so  that  the 
mineral  separates  along  or  parallel  to  these  planes  far  more 
readily  than  in  any  other  direction.  This  property  is  named 
cleavage,  and  these  planes  cleavage-planes.  They  have  a 
strictly  definite  position,  and  do  not  show  any  transition  or 
gradual  passage  into  the  greater  coherence  in  other  direc- 
tions. The  number  of  these  parallel  cleavage-planes  is  alto- 
gether indefinite ;  so  that  the  only  limit  that  can  be  as- 
signed to  the  divisibility  of  some  minerals,  as  gypsum  and 
mica,  arises  from  the  coarseness  of  our  instruments. 

These  minima  of  coherence  or  cleavage-planes  are  always 
parallel  to  some  face  of  the  crystal,  and  similar  equal  mini- 
ma occur  parallel  to  every  other  face  of  the  same  form. 
Hence  they  are  always  equal  in  number  to  the  faces  of  the 
form,  and  the  figures  produced  by  cleavage  agree  in  every 
point  with  true  crystals,  except  that  they  are  artificial. 
They  are  thus  most  simply  and  conveniently  described  by 
the  same  terms  and  signs  as  the  faces  of  crystals.  Some 
minerals  cleave  in  several  directions  parallel  to  the  faces  of 
different  forms,  but  the  cleavage  is  generally  more  easily 
obtained  and  more  perfect  in  one  direction  than  in  the 
others,  This  complex  cleavage  is  well  seen  in  calc-spar 
and  fluor  spar,  and  very  remarkably  in  zinc-blende,  where 


PHYSICAL   PROPERTIES    OF    MINERALS.  77 

it  takes  place  in  no  less  than  six  directions.  As  in  each  of 
these  the  division  may  be  indefinitely  continued,  it  is  clear 
that  no  lamellar  structure  in  any  proper  sense  can  be  as- 
signed to  the  mineral.  All  that  can  be  affirmed  is,  that 
contiguous  atoms  have  less  coherence  in  the  normal  of  these 
planes  than  in  other  directions.  When  the  cleavage  takes 
place  in  three  directions,  it  of  course  produces  a  perfect 
crystal  form,  from  which  the  system  of  crystallization  and 
angular  dimensions  of  the  species  may  be  discovered,  and 
is  thus  often  of  very  great  importance. 

The  common  cleavage  in  the  different  systems  is  as  fol- 
lows, those  of  most  frequent  occurrence  being  put  in  italics. 
(1.)  In  the  tessera),  Octahedric,  O,  along  the  faces  of  the 
octahedron ;  Bexahedric,  ooOoo  ,  alonij  those  of  the  cube , 
and  Dodecahedric,  o>O.  (2.)  In  the  tetragonal  system, 
Pyramidal,  P  or  2Poo ;  Prismatic,  ooP  or  ooPoo;  or  Ba- 
sal, OP.  (3.)  In  the  hexagonal  system  with  holohedric 
forms,  Pyramidal,  P  or  P2 ;  Prismatic,  ooP  or  ooP2  ;  or 
Basal,  OP ;  with  rhombohedral  forms,  EhomboJiedric,  R ; 
Prismatic,  oo  R ;  or  Basal,  OR.  (4.)  In  the  rhombic  sys- 
tem, Pyramidal,  P;  Prismatic,  ooP;  Makro  or  Brachy- 
domatic,  Poo  or  Poo;  Basal,  OP;  Macrodiagonal,  ooPoo; 
or  Br 'achy 'diagonal,  ooPoo .  (5.)  In  the  monoclinohedric 
system,  Hemipyramidal,  P  or— P;  Prismatic,  ooP;  Clin- 
odomatie  (P^o) ;  Hemidomatic,  Poo  or— Poo;  Basal,  OP; 
Orthodiagonal,  ooPoo;  or  Clinodiagonal  (ooPoo).  (6.) 
In  the  triclinohedric  system,  Hemiprismatic,  ooP'  oroo'P; 
Hemidomatic  either  along  the  macrodome  or  brachydome ; 
Basal,  OP;  Macrodiagonal,  ooPoo;  or  Br  achy  diagonal, 

00  P  00.     . 

In  some  minerals  the  cleavage  is  readily  procured ;  in 
others  only  with  extreme  difficulty.  The  planes  produced 
also  vary  much  in  their  degree  of  perfection,  being  highly 
perfect  in  some,  as  mica  and  gypsum ;  imperfect  in  others, 


78  A    POPULAR   TREATISE    ON    GESTS. 

as  garnet  and  quartz.  In  a  very  few  crystalline  minerals 
cleavage-planes  can  hardly  be  said  to  exist.  Cleavage  must 
be  carefully  distinguished  from  the  planes  of  union  in  twin 
crystals,  and  the  division-planes  in  the  laminar  minerals. 

Fraeture  surfaces  are  formed  when  a  mineral  breaks  in 
a  direction  different  from  the  cleavage-planes.  They  are 
consequently  most  readily  observed  when  the  cleavage  is 
least  perfect.  The  form  of  the  fracture  is  named  conchoidal 
when  composed  of  concave  and  convex  surfaces  like  shells, 
even  when  nearly  free  from  inequalities.  The  character  of 
the  surface  is  smooth  /  or  splintery  when  covered  by  small 
wedge-shaped  splinters  adhering  by  the  thicker  end;  or 
hackly  when  covered  by  small  slightly-bent  inequalities,  as 
in  iron  and  other  malleable  bodies ;  or  earthy  when  it  shows 
only  fine  dust. 

Hardness  and  Tenacity. 

The  hardness  of  minerals,  or  their  power  of  resisting  any 
attempt  to  separate  their  parts,  is  also  an  important  charac- 
ter. As  it  differs  considerably  in  the  same  species,  accord- 
ing to  the  direction  and  the  surface  on  which  the  trial  is 
made,  its  accurate  determination  is  difficult,  and  the  utmost 
that  can  usually  be  obtained  is  a  mere  approximation  found 
by  comparing  different  minerals  one  with  another.  For 
this  purpose  Mobs  has  given  the  following  scale : 

1.  Talc,  of  a  white  or  greenish  color. 

2.  Rock-salt,  a  pure  cleavable  variety,  or  semi-transparent  uncrystallizea 
gypsum,,  the  transparent  and  crystallized  varieties  being  generally  too  soft. 

8.   Calcareous  spar,  a  cleavable  variety. 

4.  Fluor  spar,  in  which  the  cleavage  is  distinct. 

5.  Apatite,\.\\Q  asparagus-stone,  or  phosphate  of  lime. 

6.  Adularia  felspar,  any  cleavable  variety. 

7.  Rock- crystal,  a  transparent  variety. 

8.  "Prismatic  topaz,  any  simple  variety. 

9.  Corundum,  from  India,  which  affords  smooth  cleavage  surfaces. 
10.  The  Diamond. 


PHYSICAL   PROPERTIES    OF    MINERALS.  79 

Two  other  degrees  are  obtained  by  interposing  foliated 
mica  between  2  and  3,  and  scapolite,  a  crystalline  variety, 
between  5  and  6.  The  former  is  .numbered  2'5,  the  lat- 
ter 5*5. 

To  ascertain  the  hardness  of  a  mineral,  first  try  which  of 
the  members  of  the  scale  is  scratched  by  it,  and  in  order  to 
save  the  specimens,  begin  with  the  highest  numbers,  and 
proceed  downward,  until  reaching  one  which  is  scratched. 
Then  take  a  finer  hard  file,  and  draw  along  its  surface,  with 
the  least  possible  force,  the  specimen  to  be  examined,  and 
also  that  mineral  in  the  scale  whose  hardness  is  immediately 
above  the  one  which  has  been  scratched.  From  the  resist- 
ance they  offer  to  the  file,  from  the  noise  occasioned  by 
their  passing  along  it,  and  from  the  quantity  of  powder  left 
on  its  surface,  their  relative  hardness  is  deduced.  When, 
after  repeated  trials,  we  are  satisfied  to  which  member  of 
the  scale  of  hardness  the  mineral  is  most  nearly  allied,  we 
say  its  hardness  (suppose  it  to  be  felspar)  is  equal  to  6,  and 
write  after  it  H.=:6'0.  If  the  mineral  do  not  exactly  cor- 
respond with  any  degree  of  the  scale,  but  is  found  to  be 
between  two  of  them,  it  is  marked  by  the  lower  with  a  de- 
cimal figure  added.  Thus,  if  more  than  6  but  less  than  7, 
it  is  expressed  H.=6'5.  In  these  experiments  we  must  be 
careful  to  employ  specimens  which  nearly  agree  in  form 
and  size,  and  also  as  much  as  possible  in  the  shape  of  their 
angles. 

Where  the  scale  of  hardness  is  wanting,  or  for  a  first 
rough  determination,  the  following  experiments  may  serve : 

Every  mineral  that  is  scratched  by  the  finger-nail  has  H.  =  2-5  or  less. 
Minerals  that  scratch  copper  have  H.  =  3  or  more. 
Polished  white  iron  has  H.  =  4-5. 
JVindow-glass  has  H.  =  5  to  5*5. 
Steel  point  or  file  has  H.  =  6  to  7. 

Hence  every  mineral  that  will  cut  or  scratch  with,  a  good  penknife  has 
H.  less  than  6. 


80  A  POPULAR  TREATISE  ON  GEMS. 

Flint  has  H.  =  7,  and  only  about  a  dozen  minerals,  including  the  precious 
atones  or  gems,  are  harder. 

Precious  stones  have  latterly  been  divided  and  arranged 
according  to  their  hardness,  in  the  following  three  classes  • 

•  > 
1.    HARD   OEMS  ;    OB  THOSE  HARDER  THAN   QUARTZ. 

Diamond.  Topaz. 

Sapphire.  Emerald. 

Ruby.  Hyacinth. 

Chrysoberyl.  Essonite. 

Spinelle.  Garnet. 

2.   SEMI-HARD   JEWELS. 

Eock  Crystal.  Opal. 

Amethyst.  Chrysolite 

Chalcedony.  Lazulite. 

Carnelian,  and  other  Obsidian, 

similar  ones.  Turquoise. 

3.   SOFT  PRECIOUS   STONES. 

Those  softer  than  Fluor-spar  ;  Malachite,  Amber,  and  Jet.      • 

Closely  allied  to  hardness  is  the  TENACITY  of  minerals,  of 
which  the  following  varieties  have  been  distinguished :  A 
mineral  is  said  to  be  brittle  when,  as  in  quartz,  on  attempt- 
ing to  cut  it  with  a  knife,  it  emits  a  grating  noise,  and  the 
particles  fly  away  in  the  form  of  dust.  It  is  sectile  or  mild 
when,  as  in  galena  and  some  varieties  of  mica,  on  cutting, 
the  particles  lose  their  connection  in  a  considerable  degree ; 
but  this  takes  place  without  noise,  and  they  do  not  fly  off, 
but  remain  on  the  knife.  And*  a  mineral  is  said  to  be  soft 
or  'ductile  when,  like  native  gold  or  lead,  it  can  be  cut  into 
slices  with  a  knife,  extended  under  the  hammer,  and  drawn 
into  wire.  From  tenacity  it  is  usual  to  distinguish  f rang  I- 
bility)  or  the  resistance  which  minerals  oppose  when  we  at- 
tempt to  break  them  into  pieces  or  fragments.  This  prop- 
erty must  not  be  confounded  with,  hardness.  Quartz  is 
hard,  and  hornblende  comparatively  soft ;  yet  the  latter  is 


PHYSICAL   PROPERTIES    OP   MINERALS.  81 

|| 

more  difficultly  frangible  than  the  former.  Flexibility 
again  expresses  the  property  possessed  by  some  minerals 
of  bending  without  breaking.  They  are  elastic,  like  mica, 
if,  when  bent,  they  spring  back  again  into  their  former  di- 
rection ;  or  merely  flexible,  when  they  can  be  -  bent  in  dif- 
ferent directions  without  breaking,  but  remain  in  their  new 
position,  as  gypsum,  talc,  asbestus,  and  all  malleable  min- 
erals. 

Specific  Gravity. 

• 

The  density  or  the  relative  weight  o*f  a  mineral,  com- 
pared with  an  equal  volume  of  pure  distilled  water,  is  named 
its  specific  gravity.  This  is  a 
most  important  character  for  dis- 
tinguishing minerals,  as  it  varies 
considerably  in  different  species, 
and  can  be  readily  ascertained 
with  much  accuracy,  and  in  many 
cases  without  at  ah1  injuring  the 
specimen.  The  whole  process  con- 
sists in  weighing  the  body,  first  in 
air,  and  then  immersed  in  water, 
the  difference  in  the  weight  being 
that  of  an  equal  bulk  of  the  latter 
fluid.  Hence,  assuming,  as  is  com- 
monly done,  the  specific  gravity 
of  pure  distilled  water  to  be  equal 

.  Fig.  94. 

to  1  or  unity,  the  specific  gravity 

(G)  of  the  other  body  is  equal  to  its  weight  in  air  (w),  di- 
vided by  the  loss  or  difference  (G)  of  weight  in  water  (or 

G=5.  A  simple  and  portable  instrument  for  finding  the 
specific  gravity  is  a  hydrometer  of  Nicholson,  fig.  94.  A 

delicate  hydrostatic  balance  gives  the  gravity  with  far  more 

40 


82  A  POPULAR  TREATISE  ON  GEMS. 

accuracy;  and  even  a  good  common  balance  is  often  pief- 
erable.  The  mineral  may  be  suspended  from  one  arm  or 
scale  by  a  fine  silk  thread  or  hair,  and  its  weight  ascer- 
tained, first  in  the  air,  and  then  in  water. 

There  are  a  few  precautions  necessary  to  insure  accuracy. 
Thus,  a  pure  specimen  must  be  selected  which  is  not  inter- 
mixed with  other  substances,  and  when  weighed  in  air  it 
should  be  quite  dry.  It  must  also  be  free  from  cavities, 
and  care  must  be  taken  that  when  weighed  in  water  no 
globules  of  air  adhere  to  its  surface,  which  render  it  lighter. 
If  the  body  imbibos  moisture,  it  should  be  allowed  to  re- 
main till  fully  saturated  before  determining  its  weight  when 
immersed,  and  it  is  sometimes  even  necessary  to  boil  the 
specimen  in  order  to  expel  the  air  from  its  pores.  Small 
crystals  or  fragments,  whose  freedom  from  mixture  can  be 
seen,  are  best  adapted  for  this  purpose.  The  specimen 
experimented  on  should  not  be  too  heavy ;  thirty  grains 
being  enough  where  the  gravity  is  low,  and  even  less  where 
it  is  high.  It  is  also  of  importance  to  repeat  the  trial,  if 
possible  with  different  -specimens,  which  will  show  whether 
any  cause  of  error  exists,  and  to  take  the  mean  of  the 
whole.  A  correction  should  be  made  for  the  variation  of 
the  temperature  of  the  water  from  60°  Fahr.,  which  is  that 
usually  chosen  as  the  standard  in  mineralogical  works. 
Where  the  difference,  however,  does  not  exceed  ten  or  fif- 
teen degrees,  this  correction  may  be  neglected,  as  it  only 
affects  the  third  or  second  decimal  figure  of  the  result. 

By  determining  the  specific  gravity  of  minerals  with  the 
hydrostatic  balance,  we  proceed,  for  instance  :  an  unknown, 
mineral  having  been  weighed  first  in  the  air,  and  then  fast- 
ened by  means  of  a  hair  and  weighed  in  water.  Such  as 
in  the  air  17  "65;  in  water  12*35.  The  loss  in  water  is, 
therefore,  5 '30;  and  this  number  indicates  the  loss  of  so 
much  bulk  of  water  displaced  by  the  mineral  putting  the 


PfiYSICAL   PROPERTIES    OF    MINERALS.  83 

specific  gravity  of  water  1*00:  x  dividing  5  into  17'65, 
make  it  equal  to  3 '5 3,  which  is  the  exact  specific  gravity 
of  the  mineral,  and  which  is  that  of  essonite.  Instead  of  a 
hydrostatic  balance,  we  may  as  "well  use  Nicholson's  hy- 
drometer, a  simple  and  A^ery  convenient  instrument,  cot> 
sisting  of  a  hollow  glass  cylinder  (A),  and  two  dishes  (B 
and  C)  filled  with  lead,  in  order  to  keep  the  instrument 
upright.  The  hydrometer  is  put-in  a  glass  vessel  (E),  filled 
with  water,  and  used  as  follows : 

1st.  The  weight  is  determined  which  is  required  to  sink 
the  instrument  to  the  mark  D  in  water. 

2d.  The  mineral  is  put  in  the  dish  A  over  the  weight 
noted,  that  'is  required,  in  addition  to  the  mineral,  to  sink 
the  hydrometer  to  D. 

3d.  The  same  experiment  is  repeated  by  putting  the 
mineral,  after  being  moistened  and  washed  with  water,  in 
the  dish  C ;  and  now  is  A— B  the  weight  of  the  mineral  in 
the  air,  and  B— b  the  weight  of  a  quantity  of  water  equal 
in  volume  to  that  of  the  mineral. 

For  instance,  let  A  =  32'8 

B  =     7-3 
C  =  15'8 

there  is  (A— b)  32*8  —  7*3  =  25*5  the  weight  of  the  mineral 
in  the  air. 

(C— b)  15*8  —  7*3  =  8*5  the  weight  of  an  equal  quantity 
of  water,  and  proceed  8*5  :  25*5  =  1  :  x 


8-5 

=  3*00,  which  is  the  proper   specific 

gravity.  For  determining  the  specific  gravity  of  substances 
or  minerals  lighter  than  water,  or  which  float  in  water,  it 
is  necessary  to  adhere  to  the  same  method  by  the  hydrome- 
ter. A  heavier  body,  such  as  lead,  after  determining  the 


84  A  POPULAR  TREATISE  ON  GEMS. 

difference  of  weight,  within  or  without  the  water,  of  both 
together,  and  then  of  the  heavier  body  alone,  the  specific 
gravity  of  the  lighter  substance  is  the  result.  And  for  de- 
termining the  specific  gravity  of  liquids,  by  means  of  the 
hydrostatic  balance,  a  glass  ball  is  applied  to  one  of  the 
arms  (its  loss  of  weight  in  pure  water  being  known),  and, 
dipping  the  same  in  the  liquid  to  be  examined,  any  addition 
and  abstraction  will  result  in  the  specific  gravity  of  the 
liquid.  The  hydrometers  of  Beaume  for  the  different 
liquids  to  be  examined,  are  employed  with  satisfactory 
results. 

That  the  specific  gravity  has  been  known  as  far  back  as 
the  thirteenth  century,  and  applied  by  the  Oriental  nations 
for  determining  the  character  of  precious  stones,  is  suffi- 
ciently proved  by  a  work  written  in  that  century  by  Mo- 
hammed Ben  Manner.  In  fact,  the  specific  gravity  is  often, 
in  connection  with  the  color,  quite  essential  in  determining 
a  gem. 

Optical  Properties  of  Minerals. 

There  are  few  more  interesting  departments  of  science 
than  the  relations  of  mineral  bodies  to  light,  and  the  modi- 
fications which  it  undergoes  either  when  passing  through 
them  or  when  reflected  from  their  surface.  In  this  place, 
however,  we  can  only  notice  these  phenomena  so  far  as 
they  point  out  distinctions  in  the  internal  constitution  of 
minerals,  or  furnish  characters  for  distinguishing  one  species 
from  another. 

Minerals,  and  even  different  specimens  of  the  same  spe- 
cies, vary  much  in  pellucidity  or  in  the  quantity  of  light 
which  can  pass  through  them.  Some  transmit  so  much 
light,  that  small  objects  can  be  clearly  seen,  or  letters  read 
when  placed  behind  them,  and  are  named  transparent. 
They  are  semi-transparent  when  the  object  is  only  seen 


PHYSICAL   PROPERTIES    OF    MINERALS.  85 

dimly,  as  through  a  cloud ;  and  translucent  when  the  light 
that  passes  through  it  is  so  obscured  that  the  objects  can 
be  no  longer  discerned.  Some  minerals  are  only  thus  trans 
lucent  on  the  thinnest  edges,  and  hi  others  even  these  trans 
mit  no  light,  and  the  body  is  named  opaque  or  untranspa 
rent.  These  degrees  pass  gradually  into  each  other,  and 
cannot  be  separated  by  any  precise  line ;  and'  this  is  also 
the  case  in  nature,  where  some  minerals  pass  through  the 
whole  scale,  as  quartz,  from  the  fine  transparent  rock-crys- 
tal to  opaque  dark-black  varieties.  Such  minerals  may  be 
described  generally  as  pellucid.  This  change  often  arises 
from  some  mixture  in  their  composition,  especially  of  me- 
tallic substances.  Perfect  opacity  is  chieny  found  in  the 
metals  or  their  compounds  with  sulphur,  though  even  these 
seem  to  transmit  light  when  reduced  to  Iamina3  of  sufficient 
thinness. 

Double  Refraction. — When  a  ray  of  light  passes  ob- 
liquely from  one  medium  into  another  of  different  density, 
it  is  bent  or  refracted  from  its  former  course.  The  line 
which  it  then  follows  forms  an  angle  with  the  perpendicu- 
lar, which  in  each  body  bears  a  certain  proportion  to 
that  at  which  the  ray  fell  upon,  it ;  or,  as  definitely  stated, 
the  sine  of  the  angle  of  refraction  has  a  fixed  ratio  to  the 
sine  of  the  angle  of  incidence,  this  ratio  being  named  the 
index  of  refraction.  This  simple  refraction  is  common  to  all 
transparent  bodies,  whether  crystalline,  amorphous,  or  fluid ; 
but  some  crystals  produce  a  still  more  remarkable  result. 
The  ray  of  light  which  entered  them  as  one  is  divided  into 
two  rays,  each  following  different  angles,  or  is  doubly  re- 
fracted. In  minerals  of  the  tesseral  system  this  property 
does  not  exist,  but  it  has  been  always  observed  in  minerals 
belonging  to  the  other  systems,  though  in  many  only  after 
they  have  been  cut  in  a. particular  manner,  or  have  been 
otherwise  properly  prepared.  It  is  most  distinctly  seen  in 


86 


A  POPULAR  TREATISE  ON  GEMS. 


crystals  of  calc-spar,  especially  in  the  beautiful  transparent 
variety  from  Iceland,  in  which  it  was  first  observed  and 
described  by  Erasmus  Bartholin  in  a  work  published  at 
Copenhagen  in  1669. 

The  subjoined  figure  will  illustrate  this  singular  proper- 
ty. It  represents  a 
rhomb  of  Iceland 
spar,  on  the  surface 
of  which  a  ray  of 
light  E  r  falls.  As 
seen  in  the  figure, 
this  ray  divides  into 
two,  one  of  which 
rod  follows  the  ordi- 
nary law  of  refrac- 
tion,  or  the  sines  of 
the  angles  of  incidence  and  refraction  maintain  a  constant 
ratio.  This  is  named  the  ordinary  ray  O.  The  other, 
hence  named  the  extraordinary  ray  E,  does  not  obey  the 
usual  law  of  the  sines,  and  has  no  general  index  of  refrac- 
tion. In  the  plane  perpendicular  to  the  axis  it  is  most 
widely  separated  from  the  ordinary  ray,  but  in  others  ob- 
lique to  it  approaches  nearer  to  O,  and  in  one  at  right 
angles  coincides,  or  there  is  no  double  refraction.  This 
plane,  or  rather  direction,  in  which  there  is  no  double  re- 
fraction, is  named  the  optical  axis  of  the  crystal,  or  the 
axis  of  double  refraction.  Now,  in  certain  minerals,  it  is 
found  that  there  is  only  one  plane  with  this  property,  where- 
as in  others  there  are  two  such  planes,  and  they  have  in 
consequence  been  divided  into  monoaxial  and  binaxial.  To 
the  former  (monoaxial)  belong  all  crystals  of  the  tetrago- 
nal and  hexagonal  systems ;  to  the  latter  (binaxial)  all 
those  of  the  three  other  systems.  In  the  former  the  optic 
axis  coincides  with,  or  is  parallel  to,  the  crystallographic 


PHYSICAL   PKOPEKTIES    OF   MINERALS.  87 

chief  axis.  In  some  crystals  the  index  of  refraction  for  the 
extraordinary  ray  E  is  greater  than  for  the  ordinary  ray  O  ; 
and  in  others  it  is  smaller.  The  former  are  said  to  have 
positive  (or  attractive),  the  latter  negative  (or  repulsive), 
double  refraction.  Quartz  is  an  example  of  the  former, 
the  index  of  refraction,  according  to  Malus,  being  for  O= 
T5484,  for  E=l*5582;  and  calc-spar  of  the  latter,  the 
index  of  O  being=  1*6543,  of  E=l*4833.  The  index  of 
E  is  in  both  cases  taken  at  its  maximum. 

According  to  Dufrenoy,  the  following  table  shows  the 
index  of  refraction  of  a  great  number  of  minerals  : 

Chromate  of  lead  ................................  2-500  to  2-974 

Diamond  ........................................  2-439  to  2'755 

Native  sulphur  ...................................  2-115 

Carbonate  of  lead  .................................  2-084 

Zircon  ...........................................  1-950 

Garnet  ...........................................  1-815 

Spinelle  ..........................................  1-812 

Blue  corundum  (sapphire)..  .  ......................  1*794 

Red         "          (ruby)  ......  '.  .....................  1-779 

White      "          (sapphire)  ........................  1-768 

Adularia  .........................................  1-764 

Cymophane  (oriental  chrysolite)  ....................  1-760 

Boracite  ..........................................  1-701 

Carbonate  strontia  ................................  1*700 


Carbonate  lime 

i  extraordinary  ray 


one  of  the  rays  ....................  1*635 

, 
the  other  ray  .....................  1'620 


(  ordinary  ray  ..........................  1-693 

Arragomte  •{ 

i  extraordinary  ray  .....................  I'o3o 

0  ( 

Sulphate  baryta  J 

J 

{  one  of  the  rays  .....................  1*640 

Yellow  topaz  -I   ,  ..  tfon 

{  the  other  ray  .......................  1  '632 

White  topaz  ......................................  l'«10 

the  rays  .......................  1'624 

J  • 


ie 


i  ordinary  ray * 1*642 

1  extraordinary  ray 1*663 

r  ordinary  ray 1'548 

Quartz{  extraordinary  ray *..1'558 


88  A   POPULAR   TREATISE   ON    GEMS. 

Eock  salt 1-557 

Chalcedony 1'553 

Gypsum 1  '525 

Opal 1-479 

Borax •. 1  '475 

Alum 1'457 

Fluor  spar 1*486 

The  higher  the  index  of  refraction,  the  more  valuable 
appear  to  be  the  individual  minerals,  as  may  be  seen  by 
the  corundum  and  topaz. 

Double  refraction,  whether  positive  or  negative,  being 
inherent  in  the  respective  mineral  substances,  forms  a  very 
'  important  distinctive  character,  and  the  following  minerals 
are  arranged  according  to  this  property : 

CRYSTALS  WITH   ONE  AXIS   AND   NEGATIVE   DOUBLE  EEFBACTION. 

Iceland  spar.  Anatase. 

Dolomite.  Tourmaline. 
Carbonate  iron.                      .      Kubellite. 

Carbonate  zinc.  Corundum. 

Meionite.  Emerald. 

Somervillite.  Phosphate  lime. 

Edingtonate.  Idocrase. 

Wernerite.  Mellite. 

Mica.  Arseniate  copper. 

Phosphate  lead.  Nepheline. 

Arseniate      "  Eed  silver. 

Molybdate     "  Dioptase. 

Cinnabar.  Alum. 

CRYSTALS  WITH   ONE   AXIS  AND   POSITIVE   DOUBLE  REFRACTION. 

Zircon.  Hydrate  magnesia. 

Quartz.  Eutil. 

Hydroxide  iron.  Oxahverite. 

'Oxide  tin.  Calcareous  Scheelite. 

Apophyllite.  Iron. 

It  should  be  observed  that  the  optic  axes  are  not  single 
lines,  but  directions  parallel  to  a  line,  or  innumerable  par- 


PHYSICAL  PROPERTIES  OF  MINERALS.          89 

allel  lines,  passing  through  every  atom  of  the  crystal.  It 
is  also  important  to  remark  that  this  property  divides  the 
systems  of  crystallization  into  three  precise  groups, — the 
tesseral,  with  single  refraction  ;  the  tetragonal  and  hexago- 
nal, with  double  refraction,  and  monoaxial ;  the  other  three 
systems  also  double,  but  binaxial.  It  is  therefore  of  use  to 
determine  the  system  to  which  a  mineral  belongs,  but  is 
not  of  great  value  as  a  character  for  distinguishing  species. 
Polarization  of  Light. — Intimately  connected  with  this 
property  is  that  of  the  polarization  of  light,  which  being 
more  easily  and  precisely  observable  than  double  refraction, 
is  in  many  cases  of  higher  value  as  a  mineralogical  character. 
By  this  term  is  meant  a  peculiar  modification  which  a  ray 
of  light  undergoes,  in  consequence  of  which  its  capability 
of  being  transmitted  or  reflected  towards  particular  sides 
is  either  wholly  or  partially  destroyed.  Thus,  if  from  a 
transparent  prism  of  tourmaline  two  thin  plates  are  cut 
parallel  to  its  axis,  they  will  transmit  light,  as  well  as  the 
prism  itself,  when"  they  are  placed  above  each  other  with 
the  chief  axis  of  both  in  the  same  direction.  But  when 
the  one  slip  of  tourmaline  is  turned  at  right  angles  to  the 
other,  either  no  light  at  all  or  very  little  is  transmitted,  and 
the  plates  consequently  appear  black.  Hence,  in  passing 
through  the  first  slip  the  rays  of  light  have  acquired  a  pe- 
culiar property,  which  renders  them  incapable  of  being 
transmitted  through  th*e  second,  except  in  a  parallel  posi- 
tion, and  they  are  then  said  to  be  polarized.  The  same 
property  is  acquired  by  a  ray  of  light  when  reflected,  at 
an  angle  of  35^°  (or  angle  of  incidence  54^°),  from  a  plate 
of  glass,  one  side  of  which  is  blackened,  or  from  some 
other  non-metallic  body.  When  such  a  ray  falls  on  a 
second  similar  mirror  at  an  equal  angle,  but  so  that  the 
plane  of  reflection  in  the  second  is  at  right  angles  to  that 
in  the  first,  it  is  no  longer  reflected,  but  wholly  absorbed. 


90 


A  POPULAR  TREATISE  ON  GEMS. 


When,  on  the  other  hand,  the  planes  of  reflection  are 
parallel,  the  ray  is  wholly  and  at  any  intermediate  angle 
partially  reflected.  A  ray  of  light  polarized  by  reflection 
is  also  incapable  of  transmission  through  a  tourmaline  slip 
in  one  position,  which,  however,  is'  at  right  angles  to  that 
in  which  a  ray  polarized  by  passing  through  another  slip 
is  not  transmitted. 

In  order  to  observe  the  polarization  of  light,  a  very  sim- 
ple instrument  will 
be  found  useful  (fig. 
•96).  At  one  end  of 
a  horizontal  board 
B  a  black  mirror  a 
is  fixed.  In  the 
middle  is  a  pillar 
to  which  a  tube  c  d 
is  fastened,  with  its 
axis  directed  to  the 
mirror  at  an  angle 
of  35£°.  On  the 
lower  end  is  a  cover  c,  with  a  small  hole  in  the  centre,  and 
at  the  upper  end  another  cover  with  a  small  black  mirror 
m  attached  to  it  by  two  arms,  as  in  the  figure,  and  also  at 
an  angle  of  35  £°.  With  this  instrument  the  mirror  m  can 
be  so  placed  in  relation  to  a  that  the  planes  of  reflection 
shall  have  any  desirable  inclination  to  exhibit  the  simple 
polarization  of  light. 

.  This  instrument  furnishes  a  simple  test  whether  minerals 
that  cleave  readily  into,  thin  lamella?  are  optically  mono- 
axial  or  binaxial.  Place  the  two  mirrors  with  their,  polari- 
zation-planes at  right  angles,  and  fix  a  plate  of  the  mineral 
with  a  little  wax  over  the  hole  c,  and  then  observe  what 
takes  place  in  the  second  mirror  during  the  time  that  the 
cover  c  is  turned  round.  If  the  mineral  belongs  to  the  bi 


Fig.  96. 


PHYSICAL    PROPERTIES    OP   MINERALS. 


91 


naxial  system,  the  light  from  the  first  mirror  «,  in  passing 
through  it,  is  doubly  refracted  and  has  its  polarization 
changed,  and  consequently  can  be  again  reflected  from  the 
second  mirror  m,  and  in  each  revolution  of.c  will  show  four 
maxima  and  four  minima  of 
intensity.  If,  on  the  contrary, 
the  mineral  is  monoaxial,\the 
ray  will  pass  through  the  lami- 
na unaltered,  and  will  not  be 
reflected  from  the  second  mir- 
ror in  any  position  of  c. 

Another  beautiful  phenom- 
enon of  polarized  light,  in  like 
manner  connected  with  the 
crystalline  structure  of  miner- 
als, is  the  colored  rings  which  • 


Fig.  98. 


Fig.  99. 


laminse  of  the  doubly-refracting  species,  when  of  a  proper 
th  ckness,  exhibit  in  certain  positions.     These  rings  are 


92  A    POPULAR    TREATISE    ON    GEMS. 

easily  seen  in  the  above  apparatus  by  interposing  a  thir: 
plate  of  gypsum  or  mica  between  the  two  mirrors.  When 
the  interposed  plate  belongs  to  a  monoaxial  mineral,  there 
is  seen  in  the  second  mirror  a  system  of  circular  concentric 
colored  rings  intersected  by  a  black  cross  (fig.  97).  If  the 
mineral  is  binaxial,  one  or  two  systems  of  elliptical  colored 
rings  appear,  each  intersected  by  a  black  stripe  (fig.  98). 
In  certain  cases  this  stripe  is  curved,  or  the  two  systems  of 
rings  unite  in  a  lemniscoidal  form  (fig.  99).  When  the 
planes  of  polarization  are  parallel,  the 
black  cross  and  stripe  appear  white 
.(fig.  100),  showing  that  in  this  direc- 
tion the  crystals  act  like  singly-refract- 
ing minerals.  Quartz,  again,  in  close 
relation  to  its  system  of 'crystalliza- 
tion, exhibits  a  Circular  polarization 
of  splendid  prismatic  colors,  which, 
on  turning  the  plate,  change  in  each 
point  in  the  order  of  the  spectrum, 

from  red  to  yellow,  green,  and  blue.  In  order  to  produce 
these  changes,  however,  in  some  specimens  the  plate  must- 
be  turned  to  the  right,  in  others  to  the  left,  showing  a  dif- 
ference in  the  Crystalline  structure. 

Pleochroism. — Closely  connected  with  double  refraction 
is  that  property  of  transparent  minerals  named  pleochroism 
(many-colored),  in  consequence  of  which  they  exhibit  dis- 
tinct colors  when  viewed  by  transmitted  light  in  different 
directions.  Crystals  of  the  tesseral  system  do  not  show 
this  property ;  while  in  those  of  the  other  systems  it  ap- 
pears in  more  or  less  perfection ;  and  in  the  tetragonal  and 
hexagonal  minerals  as  dichroism  (two  colors),  in  the  rhom- 
bic and  clinohedric  systems  as  trichroism  (three  colors). 
In  most  cases  these  changes  of  color  are  not  very  decided, 
and  appear  rather  as  different  tints  or  shades  than  as  dis- 


PHYSICAL    PKOPERTIKS    OF    MINERALS.  9c 

tinct  colors.  The  most  remarkable  of  dichromatic  minerals 
are  the  magnesian  mica  from  Vesuvius,  the  tourmaline  and 
ripidolite ;  of  trichromatic,  the  iolite,  the  andalusite  from 
Brazil,  the  diaspore  from  Schemnitz,  and  the  axinite. 

Change  of  Colors — Changing  Colors — Iridescence. 

Some  crystalline  minerals  exhibit  a  very  lively  play  or 
change  of  colors  from  reflected  light  in  certain  Directions. 
It  is  well  seen  in  many  various  hues  on  the  cleavage-planes 
of  Labrador  felspar,  and  seems  produced  by  a  multitude  of 
very  thin  quadrangular  pores,  interposed  in  the  mineral 
like  minute  parallel  lamina?.  On  the  cleavage-planes  of  the 
hypersthene  it  appears  copper-red,  and  is  occasioned  by 
numerous  small  brown  or  black  laminae  of  some  foreign 

O 

substance  interposed  in  a  parallel  position  between  -the 
planes  of  the  hypersthene.  The  chatoyant,  or  changing 
colors  of  the  sun-stone,  arise  from  scales  of  iron-glance  simi- 
larly interposed.  The  play  of  color  in  the  noble  opal  seems 
to  be  produced  very  nearly  in  the  same  manner  with  that 
in  the  labradorite.  A  similar  opalescence  is  seen  in  certain 
minerals  when  cut  in  particular  forms.  In  the"  sapphire, 
cut  hemispherically  over  the  chief  axis,  it  appears  like  a 
star  with  six  rays  ;  in  certain  varieties  of  chrysoberyl  and 
adularia  it  has  a  bluish  tint ;  and  is  also  very  remarkable  in 
the  cat's-eye  variety  of  quartz.  Iridescence  often  arises 
from  very  fine  fissures,  producing  semicircular  arches  of 
prismatic  tints,  which,  like  the  colors  of  thin  plates  in  gen- 
eral, are  referred  to  the  interference  of  light. 

Lustre  and  Color.  :  "^  ;'  * . " 

Though  these  properties  admit  of  no  precise  or  mathe- 
matical determination,  they  are  of  considerable  value  in 


94  A  POPULAR  TREATISE  ON  GEMS. 

mineralogy.  One  highly  important  distinction  founded  on 
them  is  that  of  minerals  of  metallic  and  non-metallrc  aspect 
or  character.  This  distinction  can  hardly  be  described  in 
words,  and  the  student  will  best  learn  to  distinguish  metal- 
lic colors  and  lustre  from  non-metallic  by  observing  them 
in  nature.  Transparency  and  opacity  nearly  coincide  with 
this  division,  the  metallic  minerals  being  almost  constantly 
opaque ;  the  non-metallic  more  or  less  transparent.  Min- 
erals which  are  perfectly  opaque,  and  show  metallic  color 
and  lustre,  are  named  metallic;  those  with  only  two  of 
these  three  properties,  semi-metallic  or  metalloid ;  and  those 
with  the  opposite  properties  non-metallic. 

I/ustre  has  reference  to  the  intensity  and  quality  of  the 
reflected  light,  considered  as  'distinct  from  color.  Several 
degrees  in  intensity  have  been  named,  (l.)  Splendent, 
when  a  mineral  reflects  light  so  perfectly  as  to  be  visible  at 
a  great  distance,  and  lively,  well-defined  images  are  formed 
in  its  faces,  as  galena,  rock-crystal,  or  calc-spar.  (2.) 
Shining,  when  the  reflected  light  is  weak,  and  only  forms 
indistinct  and  cloudy  images,  as  heavy  spar.  (3.)  Glisten- 
ing, when  the  reflected  light  is  so  feeble  as  not  to  be  ob- 
servable at  a  greater  distance  than  arm's  length,  and  the- 
surface  can  no  longer  form  an  image.  (4.)  Glimmering, 
when  the  mineral  held  near  the  eye  in  full  clear  daylight 
presents  only  a  number  of  small  shining  points,  as  red 
haematite  and  granular  limestone.  When,  as  in  chalk,  the 
lustre  is  so  feeble  as  to  be  indiscernible,  it  is  said  to  be  dull. 

In  regard  to  the  kind  or  quality  of  the  lustre,  the  follow- 
ing varieties  are  distinguished: — (1.)  The  metallic,  seen  in 
much  perfection  in  native  metals  and  their  compounds  with 
sulphur,  and  imperfectly  in  glance  coal.  (2.)  Adamantine, 
found  in  beautiful  perfection  in  the  diamond,  and  in  some 
varieties  of  blende  and  carbonate  of  lead.  (3.)  Vitreous  or 
glassy,  seen  in  rock-crystal  or  common  glass,  or  inclining 


PHYSICAL    PROPERTIES    OP   MTJTERALS.  95 

to  adamantine  in  flint-glass.  (4..)  Resinous,  when  the  body 
appears  as  if  smeared  with  oil,  as  in  pitch-stone  and  garnet. 
(5.)  Pearly,  like  mother-of-pearl,  seen  in  stilbite,  gypsum, 
mica.  (6.)  Silky,  the  glimmering  lustre  seen  on  fine  fibrous 
aggregates  like  amianthus. 

Color. — This  property  is  not  in  all  cases  of  equal  value 
as  a  character.  Thus  some  minerals  are  naturally  colored, 
showing  in  all  modes  of  their  occurrence  one  determinate 
color,  which  is  therefore  essential,  and  forms  a  characteristic 
of  the  species.  This  class  includes  the  metals,  pyrites, 
blendes,  with  many  metallic  oxides  and  salts.  A  second 
class  of  minerals  are  colorless,  their  purest  forms  being 
white,  or  clear  like  water,  as  ice,  calc-spar,  quartz,  adularia, 
and  many  silicates.  But  these  minerals  are  occasionally 
colored — that  is,  accidentally  tinged,  sometimes  from  the 
chemical  or  mechanical  admixture  of  some  coloring  sub- 
stance, as  a  metallic  oxide,  carbon,  or  particles  of  colored 
minerals ;  at  other  times  from  the  substitution  of  a  colored 
for  an  uncolored  isomorphous  element.  The  colors  of  these 
minerals  therefore  vary  indefinitely,  and  can  never  charac- 
terize the  species,  but  only  its  varieties.  Thus,  quartz, 
calc-spar,  fluor  spar,  gypsum,  and  felspar  are  often  colored 
accidentally  by  pigments  mechanically  mixed ;  and  horn- 
blende, augite,  garnet,  and  other  colorless  silicates,  acquire 
green,  brown,  red,  or  black  tints  from  the  introduction  of 
the  isomorphic  coloring  elements. 

"Werner,  who  bestowed  much  attention  on  this  portion 
of  mineralogy,  distinguished  eight  principal  colors, — white, 
gray,  black,  blue,  green,  yellow,  red,  and  brown, — each 
with  several  varieties  or  shades  arising  from  intermixture 
with  the  other  colors.  He  also  divided  them  into  metallic 
and  non-metallic  as  follows : 


96  A  POPULAR  TREATISE  ON  GEMS. 


METALLIC   COLORS. 

1.  White. — (1.)  Silver-white,  as  in  Icucopyrite  and  native  silver.     (2.) 
Tin-white';  native  antimony. 

2.  .Gray.— (1.)  Lead-gray;  galena  or  lead  glance.     (2.)  Steel-gray;  na- 
tive platina. 

8.  Black. — (1.)  Iron-black;  magnetite. 

4.  Yellow. — (1.)  Brass-yellow;   chalcopyrite.     (2.)  Bronze-yellow;   iron 
pyrites.     (3.)  Gold-yellqw  ;  native  gold. 

5.  Red. — (1.)  Copper-red;  native  copper  and  nickeline. 

NON-METALLIC   COLORS. 

1.  White. — (1.)   Snow-white  ;    new-fallen  snow,    Carrara  marble,   and 
common  quartz.     (2.)  Eeddish-white ;  heavy  spar.    (3.)  Yellowish-white; 
chalk.     (4.)   Grayish-white ;    quartz.      (5.)    Greenish-white ;    amianthus. 
(0.)  Milk-white;  skimmed  milk,  chalcedony. 

2.  Gray. — (1.)  Bluish-gray;  limestone.     (2.)  Pearl-gray;  porcelain  jas- 
per, and  rarely  quartz..    (3.)  Smoke-gray  or  brownish-gray;  dense  smoke, 
dark  varieties  of  flint.    (4.)  Greenish-gray;  clay-slate  and-whet-slate.     (5.) 
Yellowish-gray;  chalcedony.     (6.)  Ash-gray;  wood-ashes,  zoisite,  zircon, 
and  slate-clay. 

3.  Slack. — (1.)  Grayish-black;  basalt,  Lydia'n  stone,  and  lucullite..    (2.) 
Velvet-black;  obsidian  and  schorl.     (3.)  Pitch-black  or  brownish-black; 
cobalt  ochre,  bituminous  coal,  and  some  varieties  of  mica.     (4.)  Greenish- 
black  or  raven- black;  hornblende.     (5.)  Bluish-black;  fluorspar. 

4.  Blue. — (1.)  Blackish-blue;  dark  varieties  of  azurite.    (2.)  Azure-blue; 
bright  varieties  of  azurite  and  lapis  lazuli.      (3.)  Violet- blue;  amethyst 
and  fluor  spar.      (4.)    Lavender-blue;   lithomarge  and  porcelain  jasper. 
(5.)  Plum-blue;  spinel  and  fluor  spar.     (6.)  Berlin-blue;  sapphire,  rock- 
salt,  cyanite.     (7.)  Smalt-blue ;  pale-colored  smalt,  gypsum.     (8.)  Duck- 
blue  ;  talc  and  corundum.     (9.)  Indigo-blue ;  earthy-blue  iron  or  vivianite. 
(10.)  Sky-blue ;  liroconite,  some  varieties  of  fluor  spar  and  of  blue  spar. 

5.  Green. — (1.)  Verdigris-green;  amazon  stone  and  liroconite.     (2.)  Cel- 
andine-green; green  earth,  Siberian  and  Brazilian  beryl.     (3.)  Mountain- 
green;    beryl,  aqua-marine  topaz.     (4.)  Leek-green;  common  actynolite 
and  prase.     (5.)  Emerald-green;    emerald,  and  some  varieties  of  green 
malachite.     (6.)   Apple-green;   chrysoprase.     (7.)    Grass-green;    uranite, 
pmaragdite,     (8.)  Blackish-green;    augite  and  precious  serpentine.     (9.) 
Pistachio-green;    chrysolite  and   epidote.      (10.)    Asparagus-green;   the 
apatite  or  asparagus-stone  from  Spain  and  Salzburg.     (11.)  Olive-green  ; 
garnet,  pitch-stone,  and  olivine.    (12.)  Oil-green;  olive-oil,  blende,  beryl. 
(13.)  Siskin-green;  uranite,  and  some  varieties  of  pyromorphite. 

6.  Yellow. — (1.)  Sulphur-yellow;    native  sulphur.     (2.)   Straw-yellow; 


PHYSICAL   PROPERTIES    OP    MINERALS.  97 

pycnite  and  karpholite.  (3.)  "Wax-yellow;  opal  and  wulfenite.  (4.)  Hon- 
ey-yellow; dark  honey,  fluor  spar,  and  beryl.  (5.)  Lemon-yellow;  rind 
of  ripe  lemons,  orpiment.  (6.)  Ochre-yellow;  yellow-earth  and  jasper. 
(7.)  Wine-yellow ;  Saxon  and  Brazilian  topaz  and  fluor  spar.  (8.)  Cream- 
yellow  or  Isabella-yellow  ;  bole  from  Strigau,  and  compact  limestone.  (9.) 
Orange-yellow,  rind  of  the  ripe  orange,  uran-ochre,  and  some  varieties  of 
wulfenite. 

7.  Red. — (1.)  Aurora,  or  morning-red ;  realgar.     (2.)  Hyacinth-red;  hya- 
cinth or  zircon,  and  garnet.    (3.)  Tile-red ;  fresh-burned  bricks,  porcelain- 
jasper,  and  heulandite.    (.4.)  Scarlet-red;  light-red  cinnabar.     (5.)  Blood- 
red;  blood,  pyrope.     (6.)  Flesh-red;  felspar  and  barytes.     (7.)  Carmine- 
red;  carmine,  spinel,  particularly  in  thin  splinters.     (8.)  Cochineal-red; 
cinnabar  and  certain  garnets.    (9.)  Crimson-red ; .  oriental  ruby  and  eryth- 
rine.     (10.)  Cclumbine-red ;    precious  garnet.     (11.)  Rose-red;  diallogite 
and  rose-quartz.    (12.)  Peach-blossom  red  ;  blossoms  of  the  peach,  red 
cobalt-ochre.      (13.)   Cherry-red;    spinel,  kermes,   and  precious  garnet. 
(14.)  Brownish-red;  reddle  and  columnar-clay  ironstone. 

8.  JBrotcn. — (1.)   Reddish- brown;   brown  blende  from  the  Hartz,  and 
zircon.     (2.)  Clove-brown  ;  the  clove,  rock-crystal,  and  axinite.     (3.)  Hair- 
brown  ;    wood-opal  and  limonite.      (4.)    Broccoli-brown ;    zircon.      (5.) 
Chestnut-brown;  Egyptian  jasper.    (6.)  Yellowish-brown;  iron  flint  and 
jasper.     (7.)  Pinchbeck-brown;  tarnished  pinchbeck,  mica.    (8.)  Wood- 
brown  ;  mountain  wood  and  old  rotten  wood.     (9.)  Liver-brown  ;  boiled 
liver,  common  jasper.     (10.)  Blackish-brown ;  mineral  pitch  and  brown 
coal. 

The  accidentally-colored  minerals  sometimes  present  two 
or  more  colors  or  tints,  even  on  a  single,  crystal;  very  re- 
markable examples  occurring  in  fluor  spar,  apatite,  sapphire, 
amethyst,  tourmaline,  and  cyanite.  This  is  still  more  com- 
mon in  compound  minerals,  on  which  the  colors  are  va- 
riously arranged  in  points,  streaks,  clouds,  veins,  stripes, 
bands,  or  in  brecciated  and  ruin-like  forms. .  Some  miner- 
als again  change  their  color  from  exposure  to  the  light, 
the  air,  or  damp.  Sometimes  merely  the  surface  is  affected 
or  tarnished,  and  then  appears  covered  as  with  a  thin  film, 
producing  in  some  minerals,  as  silver,  arsenic,  bismuth,  only 
one  color ;  in  others,  as  copper  pyrites,  hematite,  stibine, 
and  common  coal,  various  or  iridescent  hues.  Occasionally 
the  change  pervades  the  whole  mineral,  the  color  some- 
V"  5  • 


98  A  POPULAR  TEEATISE  ON  GEMS. 

times  becoming  paler,  or  disappearing,  as  in  ehrysoprase 
and  rose-quartz ;  at  other  times  darker,  as  in  brown  spar, 
siderite,  and  rhodonite.  In  a  few  minerals  a  complete 
change  of  color  takes  place,  as  in  the  chlorophaeite  of  the 
Western  Isles,  which,  on  exposure  for  a  few  hours,  passes 
from  a  transparent  yellow-gre'en  to  black.  These  mutations 
seem  generally  connected  with  some  chemical  change.  The 
tarnished  colors  sometimes  only  appear  on  certain  faces  of 
a  crystal  belonging  to  a  peculiar  form.  Thus  a  crystal  of 
copper  pyrites  (like  fig.  35)  has  one  face  P'  free  from  tar- 
nish ;  the  faces  b  and  c,  close  to  P',  are  dark  blue ;  the  re- 
mainder of  c,  first  violet,  and  then,  close  to  P,  gold-yellow. 
The  color  of  the  powder  formed  when  a  mineral  is  scratched 
by  a  hard  body  is  often *different  from  that  of  the  solid 
mass.  This  is  named  the  streak,  and  is  very  characteristic 
of  many  minerals.  It  also  often  shows  a  peculiar  lustre 
where  the  mineral  is  soft,  as  in  talc  and  steatite. 

Phosphorescence,  Electricity,  Magnetism. 

Phosphorescence  is  the  property  possessed  by  particular 
minerals  of  producing  light  in  certain  circumstances  with- 
out combustion  or  ignition.  Thus  some  minerals  appear 
luminous  when  taken  into  the  dark  after  being  for  a  time 
exposed  to  the  sun's  rays,  or  even  to  the  ordinary  daylight. 
Many  diamonds  and  calcined  barytes  exhibit  this  property 
in  a  remarkable  degree ;  less  so,  arragonite,  calc-spar,  and 
chalk ;  and  in  a  still  inferior  degree,  rock-salt,  fibrous  gyp- 
sum, and  fluor  spar.  Many  minerals,  including  the  greater 
part  of  those  thus  rendered  -phosphorescent  by  the  influ- 
ence of  the  sun,  also  become  so  through  heat.  Thus  some 
topazes,  diamonds,  and  varieties  of  fluor  spar,  become  lumi- 
nous by  the  heat  of  the  hand ;  other  varieties  of  fluor  spar 
and  the  phosphorite  require  a  temperature  near  that  of  boil- 


PHYSICAL   PEOPEETIES    OF   ]Sn>TERALS.  99 

ing  water;  while  calc-spar  and  many  silicates  are  only 
phosphorescent  at  from  400°  to  700°  Fahr.  Electricity 
produces  it  in  some  minerals,  as  in  green  fluor  spar  and 
calcined  barytes.  In  others  it  is  excited  when  they  are 
struck,  rubbed,  split,  or  broken ;  as  many  varieties  of  zinc- 
blende  and  dolomite  when  scratched  with  a  quill,  pieces  of 
quartz  when  rubbed  on  each  other,  and  plates  of  mica  when 
suddenly  separated. 

Friction,  pressure,  and  heat  also  excite  electricity  in 
minerals.  To  observe  this  property;  delicate  electroscopes 
are  required,  formed  of  a  light  needle,  terminating  at  both 
ends  in  small  balls,  and  suspended  horizontally  on  a  steel 
pivot  by  an  agate  cup.  Such  an  instrument  can  be  nega- 
tively electrified  by  touching  it  with  a  stick  of  sealing-wax, 
excited  by  rubbing,  or  positively  when  the  wax  is  only 
brought  so  n^ear  as  to  attract  the  needle.  When  the  in- 
strument is  in  this  state  the  mineral,  if  also  rendered  elec- 
tric by  heat  or  friction,  will  attract  or  repel  the  needle  ac- 
cording as  it  has  acquired  electricity  of  an  opposite  or 
similar  kind ;  but  if  the  mineral  is  not  electric,  it  will  at- 
tract the  needle  in  both  conditions  alike.  Most  precious 
stones  become  electrical  from  friction,  and  are  either  posi- 
tive or  negative  according  as  their  surface  is  smooth  or 
rough.  Pressure  even  between  the  fingers  will  excite  dis- 
tinct positive  electricity  in  pieces  of  transparent  double- 
refracting  calc-spar.  Topaz,  arragonite,  fluor  spar,  car- 
bonate of  lead,  quartz,  and  other  minerals  show  this 
property. 

Heat  or  change  of  temperature  excites  electricity  in  many 
crystals,  as  in  tourmaline,  calamine,  topaz,  calc-spar,  beryl, 
barytes,  fluor  spar,  diamond,  garnet,  and  others,  which  are 
hence  said  to  be  thermo  or  pyroelectric.  Some  acquire 
polar  pyro-electricity,  or  the  two  electricities  appear  in  op- 
posite parts  of  the  crystal,  which  are  named,  its  electric 


100  A  POPULAR  TREATISE  ON  GEMS. 

poles.  Each  pole  is  alternately  positive  and  negative,— the 
one  when  the  mineral  is  heating,  the  other  when  it  is  cool- 
ing. The  poles  that  become  positive  during  an  increase  of 
temperature  are  named  analogue ;  those  that  become  nega- 
tive in  the  same  condition,  antilogue  poles,  as  shown  in  this 
table : 


Temperature. 
-f-  or  rising  ). 
—  or  falling  f 

Produces 

in  analogue 
poles 

Electricity, 
j  -j-  or  vitreous. 
1  —  or  resinous. 

-j-  or  rising  ) 
—  or  fulling  j 

in  antilogue 
poles 

j  —  or  resinous. 
1  -f-  or  vitreous. 

As  already  noticed,  many  polar  electric  minerals  are  also 
remarkable  for  their  hemimorphic  crystal  forms.  The  num- 
ber and  distribution  of  the  poles  likewise  vary.  In  many 
monoaxial  minerals,  as  tourmaline  and  calamine,  there  are 
only  two  poles,  one  at  each  end  of  the  chief  a^is ;  whereas 
boracite  has  eight  poles  corresponding  to  the  angles  of  the 
cube.  In  prehnite  and- topaz,  again,  two  antilogue  poles 
occur  on  the  obtuse  lateral  edges  of  the  prism  ooP,  and 
one  analogue  pole  corresponding  to  the  macrodiagonal 
chief  section,  or  in  the  middle  of  the  diagonal  joining  the 
obtuse  edges.  The  power  of  retaining  the  electricity  ac- 
quired by  rubbing,  for  a  longer  time,  varies  in  different 
minerals  and  gems ;  and  as  the  latter  are  all  electric,  this 
property  may  sometimes  be  used  as  a  distinguishing  char- 
acter as  to  the  length  of  retaining  the  electricity.  Abbe 
Haily  found,  in  his  experiments,  that  many  precious  stones 
lose  their  electric  power  after  a  few  moments,  whereas  some 
will  retain  the  same  for  twenty-four  hours  longer.  The 
Brazilian  topaz  affected  the  needle,  even  after  thirty-two 
hours. 

Magnetism,  or  the  power  to  act  on  the  magnetic  needle, 
is  very  characteristic  of  the  few  minerals  in  which  it  occurs, 
chiefly  ores  of  iron  or  nickel.  It  is  either  simple,  attracting 


PHYSICAL   PROPERTIES    OF    MINERALS.  101 

both 'poles  of  the  needle ;  or  polar,  when  one  part  attracts, 
and  another  repels  the  same  pole.  Some  magnetic  iron 
ores,  or  natural  magnets,  possess  polar  magnetism ;  while 
the  common  varieties,  meteoric  iron,  magnetic  pyrites, 
precious  garnet,  and  other  minerals,  are  simply  magnetic. 
Most  minerals  'are  only  attracted  by  the  magnet,  but  do 
not  themselves  attract  iron. 

Smell,  taste,. and.  touch  furnish  a  few  characters  of  min- 
erals. Most  have  no  smell,  but  some  give  out  a  peculiar 
odor  when  rubbed :  as  quartz,  an  empyreumatic-  odor,  or 
smell  of  burning ;  fluor  spar,  of  chlorine ;  clay,  of  clay ; 
some  limestones  and  marls,  of  bitumen,  or  a  fetid  odor. 
Aluminous  minerals  acquire  a  smell  when  breathed  on. 
Other  odors  caused  by  heat,  and  often  highly  character- 
istic, are  noticed  under  tests  by  the  blo\vpipe. 

Taste  is  produced  by  all  the  salts  soluble  in  water. 
Some  are  saline,  like  common  salt ;  sweetish  astringent, 
like  alum ;  astringent  like  blue  vitriol ;  bitter,  like  epsom 
salts;  cooling,  like  saltpetre;  pungent,  like  sal-ammoniac; 
alkaline,  like  soda ;  acid  or  sour,  like  sassoline,  &c. 

Touch. — Some  minerals  are  distinguished  by  a  greasy 
feeling,  like  talc ;  others  feel  meagre,  like  clay ;  others  cold. 
The  last  character  readily  distinguishes  true  gems  from 
their  imitations  in  glass.. 


102  A   POPULAR   TREATISE    ON   GEMS. 


CHAPTER  III. 

CHEMICAL  PROPERTIES  OF  MINERALS. 

THE  consideration  of  the  chemical  nature  of  minerals, — 
that  is,  of  the  elements  that  enter  into  their  composition, — 
of  the  manner  in  which  these  elements  combine,  and  the 
variations  in  proportion  which  they  may  undergo  without 
destroying  the.identity  of  the  species,  forms  an  important 
branch  of  mineralogical  science.  The. methods  of  detect- 
ing the  different  elements,  and  the  characters  which  are 
thus  furnished  for  the  discrimination  of  minerals,  are  also 
of  much  value.  This  is  especially  true  of  the  metallic  ores 
and  other  .substances,  sought  not  as  objects  of  curiosity, 
but  for  their  economic  qualities. 

Composition  of  Minerals. 

At  present  about  sixty  elements,  or  substances  which 
have  not  been  decomposed,  are  known.  These  are  divided 
into  metallic  and  non-metallic,  a  distinction  of  importance 
in  mineralogy,  though  not  always  to  be  carried  out  with 
precision.  The  non-metallic  elements  are  rarely  of  semi- 
metallic  aspect,  and  are  bad  conductors  of  heat  and  elec- 
tricity. Some  are  commonly  gaseous — oxygen,  hydrogen, 
nitrogen,  chlorine,  and  fluorine  ;  one  fluid — bromine ;  the 
others  solid — carbon,  phosphorus,  'sulphur,  boron,  selenium, 
and  iodine.  The  metallic  elements  are,  except  mercury, 
solid  at  usual  temperatures,  have  generally  a  metallic  aspect, 
and  are  good  conductors  of  heat  and  electricity.  They  are 
divided  into  light  and  heavy  metals,  the  former  with  a 


CHEMICAL    PROPERTIES    OF    MINERALS.  103 

specific  gravity  under  5,  and  a  great  affinity  for  oxygen, 
and  again  distinguished  as  either  alkali-metals,  potassium 
•(or  kalium),  sodium  (or  natrium),  lithium,  barium,  stron- 
tium, and  calcium  ; — or  earth-metals,  magnesium,  lanthani- 
um,  yttrium,  glucinum,  aluminium,  zirconium,  silicium. 
The  heavy  metals,  with  a  specific  gravity  above  5,  are 
divided  into  noble,  which  can  be  reduced  or  separated,  from- 
oxygen,  by  heat  alone ;  and  ignoble,  whose  affinity  for 
oxygen  renders  them  irreducible  without  other  agents. 
Some  of  the  latter  are  brittle  and  difficultly  fusible, — tho- 
rium, titanium,  tantalium  (columbium),  tungsten  (wolfra- 
mium),  molybdenum,  vanadium,  chromium,  uranium,  man- 
ganese, and  cerium ;  others  are  brittle  and  easily  fusible  or 
volatile — arsenic,  antimony,  tellurium,  and  bismuth;  and 
others  malleable — zinc,  cadmium,  tin,  lead,  iron,  cobalt, 
nickel,  and  copper.  The  noble  metals  are, — quicksilver, 
silver,  gold,  platinum,  palladium,  rhodium,  iridium,  and 
osmium. 

All  the  chemical  combinations  observed  in  the  mineral 
kingdom  follow  the  law  of  definite  proportions;  that  is, 
two  elements  always  combine  either  in  the  same  proportion, 
or  so  that  the  quantity  of  the  one  is  multiplied  by  two, 
three,  four,  or  some  other  definite  number  seldom  very 
large.  As  the  same  law  prevails  throughout  the  whole 
range  of  elements,  by  assuming  any  one,  usually  hydrogen 
or  oxygen,  as  unity  or  1,  and  determining  froqfc  experiment 
the  simple  proportion  in  which  the  others  combine  with  it, 
a  series  of  numbers  is  obtained  which  als"o  expresses  the 
proportions  in  which  all  these  elements  combine  with  each 
other.  These  numbers,  therefore,  mark  the  combining 
proportions  or  equivalents,  as  they  are  named,  of  the  ele- 
ments. They  are  also  named  atomic  weights,  on  the  sup- 
position that  matter  consists  of  definite  atoms,  and  that  its 
combinations  consist  of  one  atom  (or  sometimes  two  atoms) 


104  A  POPULAR  TREATISE  ON  GEMS. 

of  one  substance,  with  one,  two,  three,  or  more  atoms  of 
another.  This  theory  is  not  free  from  difficulties,  but  the 
language  is  often  convenient.  To  designate  the  elements, 
chemists  generally  employ  the  first  letter  or  letters  of  their 
Latin  names.  These  signs  also  .indicate  one  atom  or 
equivalent  of  the  element.  Thus,  O  means  oxygen  in  the 
proportion  of  one  atom  ;  H,  hydrogen  in  the  same  propor- 
tion ;  N",  an  atom  of  nitrogen ;  Na,  an  equivalent  propor- 
tion of  natrium  or  sodium.  These  signs  and  the  equivalent 
weights  are  given  in  the  table  on  next  page,  in  one  column 
of  which  hydrogen  is  taken  as  unity,  in  the  other  oxygen. 
Thte  elements  are  arranged  according  to  Berzelius,  begin- 
ning with  the  most  electro-positive,  and  ending  with  the 
most  electro-negative. 

All  these  elements  occur  in  minerals,  but  not  more  than 
twenty  are  common,  and  only  about  twelve  abundant. 
They  are  also  very  rare  in  their  simple  or  uncombined  state ; 
only  'carbon  in  the  diamond  and  graphite,  sulphur,  and 
about  a  dozen  of  the  native  metals,  being  thus  known. 
More  frequently  minerals  consist  of  two  or  more  elements 
combined  in  accordance  with  those  laws  which  prevail  in 
inorganic  compounds.  The  most  important  of  these  laws 
is  that  the  combinations  are  binary;  that  is,  that  the  ele- 
ments unite  in  pairs,  which  may  again  unite  either  with 
another  compound  of  two,  or  with  a  single  element.  Inor- 
ganic compdtnds  also  are  generally  distinguished  from  or- 
ganic by  their  greater  simplicity. 


CHEMICAL   PROPERTIES    OF   MINERALS. 


105 


TABLE  I. 
Elements  arranged  in  Electro-  Chemical  order. 


Name. 

Sign. 

Atomic  Weight. 

Name. 

Sign. 

Atomic  Weight 

H=l 

0=100. 

H=l 

O=100. 

Potassium  .... 
Sodiam.       ... 

K 
Na 
Li 
NH3 
Ba 
Sr 
Ca 
Mg 

Fe 
Ni 
Co 
Zn 
Cd 
Sn 
Pb 
Bi 
Cu 

?* 
Pi 
Rh 
Ru 
Ir 
Pt 

03 

Au 
H 

c{ 

39-2 
23-2 
7 
17 
68-6 
44 
20 
12-5 
32 
28 
29 
30 
32-2 
56 
59 
104 
208 
31-7 
100 
108 
53-3 
52 

99 
99 
99 
168 
1 
15 
22'2 
6 

488-85 
290-9 
86-9 

856-88 
547-28 
251-5 
'    154-5 
402-51 
350-53 
362-8 
375 
406-59 
696-76 
735-29 
1294-5 
*2600 
395-69 
1250 
1349-66 
665*84 
651-4 

1283-26 

1233-26 
1244-21 
*2458-83 
*12-48 
tl87-5 
J277-31 
75-415 

Glucinum  
'Aluminium  .  .  . 
.Zirconium 
[Thorium 

Q 

Al 
Zr 
Th 
Ce 
La 
D 

u 

Mn 
B 

Ti 
Ta 
Nb 
Pp 
W 
Mo 
V 
Cr 
Te 
Sb 
As 
P 
N 
Se 
S 
O 

I 

Br 
Ci 

F 

7 
13-7 
22-5 
59-6 
46 
36? 

60 
28 
11 
25 
185 

92* 
46 
66-6 
26-3 
64 
122 
75 
31 
14 
40 
16 
8 
126 
78-4 
36 
18-7 

86-5     1 
*342-33 
*S40'4 
744-90 
575 

746-86 
345-89 
136-2 
303-63 
1153-715 
.... 

1150:78 
575-83 
855-8 
328-59 
802-12 
1529-2 
*940-08 
*392-28 
*175-06 
494-58 
200-75 
100 
*1586 
*999-62 
*443-28 
*233'SO 

Lithium  

Ammonium... 
Barium 

Cerium 

Strontium  

jLanthanium..  . 
iDidjrmium  ... 
I  Uranium  
(Manganese  ... 
Boron 

Calcium. 

Magnesium  .  .  . 
Yttrium  

Iron  

Nickel  

Titanium.  . 

Cobalt  

Tantalium.  
;  Niobium  . 
'Pelopium?  
jWolframium.. 
Molybdenum. 
i  Vanadium  
Chromium...  . 

1  Zinc  

Cadmium  
Tin. 

Lead  
Bismuth  

Copper  .  . 

Mercury 

Silver..  
Palladium  
Rhodium  .  .  . 

i  Antimony  
Arsenic  . 

Phosphorus... 
Nitrogen  

Ruthenium  

Selenium  >  
Sulphur.  . 

Platinum  . 

Osmium 

Oxvgen  

Gold. 

i  Iodine 

Hydrogen  
Siliciuni  

Bromine  . 

Chlorine  

Carbon  .  .  . 

! 

*  Double  atoms, 
t  L.  Gmelin,  who  considers  silica  as  composed  of  one  atom  base  and  two 
oxygen. 
%  Berzelius. 

The  above  list  includes  ammonium,  usually  considered -a 
compound  body,  and  omits  the  two  new  metals,  erbium 
.and"  terbium. 

The  following  principles  are  observed  in  designating  the 
combinations  of  these  elementary  substances :  For  those  of 

5- 


106  A  POPULAR  TEEATISE  ON  GEMS. 

the  first  order  the  signs  of  the  two  components  are  con- 
joined, and  the  number  of  atoms  or  equivalents  of  each  ex- 
pressed by  a  number  following  the  sign  like  an  algebraic 
exponent.  Thus,  SO,  SO2,  SO3,  are  the  combinations  of 
one  atom  sulphur  with  one,  two,  and  three  atoms  of  oxygen  ; 
FeS,  FeS2,  of  one  atom  of  iron  with  one  or  two  of  sulphur. 
But  as  combinations  with  oxygen  and  sulphur  are  very 
numerous  in  the  mineral  kingdom,  Berzelius,  to  whom 
science  is  indebted  for  this  system  of  signs,  marks  the  atoms 
of  oxygen  by  dots  over  the,  sign  of  the  other  element,  and 
those  of  sulphur  by  an  accent ;  the  above  compounds  being 
then  designated  thus — S,  S,  S,  and  Fe',  Fe".  In  some  cases 
two  atoms  of  a  base  combine  with  three  or  five  of  oxygen 
or  sulphur,  as  APO3,  Fe2S3.  In  such  cases  Berzelius  marks 
the  double  atom  by  a  line  drawn  through  the  sign  of  the 
single  atom ;  thus,  Al  is  two  atoms  aluminium  with  three 
of  oxygen,  or  alumina ;  -On,  two  of  copper  with  one  of  oxy- 
gen, or  oxide  of  copper.  Where  a  number  is  prefixed  to  the 
sign  like  a  coefficient  in  algebra,  it  includes  both  elements  of 
the  combination ;  thus  H  is  one  atom  water,  2  H  two ;  CaC 
is  one  atom  carbonate  of  lime,  2  CaC  two  atoms,  includ- 
ing, of  course,  two  of  calcium,  two  of  carbon,  and  six  of 
oxygen. 

The  most  common  and  important  binary  compounds  are 
those  with  oxygen,  contained  in  the  following  table,  with 
their  signs,  atomic  numbers,  and  amount  of  oxygen  in  100 
parts.  The  more  electro-negative  are  named  acids,  which 
are  often  soluble  in  water,  and  then  render  blue  vegetable 
colors  red.  The  more  electro-positive  are  named  oxides  or 
bases,  and  show  great  affinity  or  attractive  power  for  the 
former.  The  most  powerful  are  the  alkaline  bases,  which 
are  colorless  and  soluble  in  water ;  less  powerful  are  the 
earths,  also  colorless,  but  insoluble  in  water : 


TABLE  II. — Binary  Compounds  with  Oxygen.    107 


Name. 

Sign. 

Atomic  Weight 

Oxyg. 
in  100 
par  ts. 

o 

«3 

f 

0 

PH 

^ 
II 

< 

0 

£ 

5 

"o 

1 

3 

0 

_ 

£ 

r3 
o 

| 

^5 
.3 
p 

rt 

00 

1 

"e3 

^0 

2 

3 

0 
^0 
d 

1 

.22 

t3 
KH 

O 

fc 

H=l. 

O=l  00. 

Alumina 

Ai 

Sb 

ft 

*Sb 
As 

'\* 
Ba 
Bi 

B* 

d 

Co 
fcb 
C'r 

bV 

Co 
60 

da 

o" 

Ke 
JPe 

Fe-f-Fe 
Pb 
Ca 

i.r 

Mg 

Mn 

VIM 

M..+MII 

Mo 
Ni 
'*' 

•>V£ 
K 
Si 
Si' 
Na 
S'r 
8* 
ta 
Th 
Sn 
Ti 
W 

ir 
u 

V 
H 
Y 
Zn 
Zr—  *Zr 

51-4 
146 
154 
162 
99 
115 
766 
232 
34  8 
22 
54 
116 
76-6 
50  3 
38 
714 
39-7 
38 
36 
80 
116 
i!2 
28 
15 
21 
36 
80 
116 
70 
37 
54 
71 
47-2 
31 
46-2 
31-2 
52 
4Q 
209 
67-6 
75 
41 
116 
68 
144 
92 
9 
40 
402 
304 

642  33 
1829-2 
1929-2 
2029-2 
1240-08 
1440-08 
95688 
2900-00 
436-20 
2750 
674-72 
1449-39 
956-78 
628-39 
475 
891  -39 
495-69 
490-05 
450-527 
1001-054 
1451-581 
1394-50 
351  -489 
186-9 
254-50 
44589 
991-77 
1437-66 
875-83 
4628 
675-06 
892-28 
588-856 
387-5 
577-31 
390-90 
647-29 
500-75 
2607-43 
844-90 
935-29 
503-68 
1450-78 
84284 
1792-72 
1155  84 
112-48 
502-51 
506-59 
114-2 

46-70 
16-40 
20-73 
24-64 

34-72 
10-45 
10-34 
68-78 
72-73 
1482' 
2070 
31-35 
47  74 
21-05 
11  12 
2017 
6326 
22-19 
29-97 
26-08 
7-17 
v28-45 
5350 
39-30 
2243 
30-25 
26-34 
34-28 
21-60 
7407 
5604 
1698 
51-61 
51  96 
25-58 
1545 
59-91 
11-51 
13  34 
21-38 
39-71 
20-67 
1333 
10  13 
26  19 
88-89 
19-90 
1974 
26-37 

Antimony  oxide 

Antimoniousacid  

Antimonic  acid  

Arsenious  acid  

Arsenic  acid  

Bary  ta  

Bismuth-  peroxide  

Boracic  acid  
Carbonic  acid  

Cerium  protoxide  

"       peroxide  

Chromium  oxide  

Chromic  acid  

Cobalt  protoxide. 

Copper  suboxide  (red) 

'  '       protoxide  (black)  .  . 
Glucina  

Iron  protoxide  

"    peroxide  (red)  

"    pro  to-  peroxide  (black) 
Lead  protoxide  

Magnesia  

Manganese  protoxide..  . 

"          peroxide. 

4i      proto-perox.  (red) 
Molybdio  acid 

Nickel  protoxide. 

Nitric  acid  

Phosphoric  acid  

Potassa  

Silica  (Gmelin) 

"      (Berzelius). 

Soda 

Strontia 

Sulphuric  acid  

Tantalic  acid  .  .  «  

Thorina  

Tin  peroxide   

Titanic  acid     

Tungstic  acid        .        ... 

Uranium  protoxide  

"         peroxide 

Vanadic  acid  .                   ... 

Water..                        .... 

Yttria  

Zinc  oxide         

Zirconia  •  

108  A  POPULAR  TREATISE  ON  GEMS. 

Similar  to  the  compounds  of  oxygen  are  those  with  sul- 
phur, usually  named  sulphurets,  and  considered  analogous 
to  the  oxidized  bases.  A  few  of  more  electro-negative 
character,  resembling  acids,  have  been  distinguished  as  sul- 
phides. Some  other  compounds  have  been  named  haloid 
gaits,  and  consist  of  certain  electro-negative  elements,  com- 
bined with  electro-positive  ones,  as  bases. 

Many  of  these  combinations  occur  as  independent  species 
in  the  mineral  kingdom,  especially  those  with,  oxygen  and 
sulphur.  Thus  the  most  abundant  of  all  minerals,  quartz, 
is  an  oxide,  and  corundum  is  of  similar  nature.  Many 
oxides  of  the  heavy  metals,  as  of  iron,  tin,  copper,  and  anti- 
mony ;  and  some  super-oxides,  as  of  lead  and  manganese 
(pyrolusite),  are  very  common.  Compounds  with  sulphur 
also  abound,  either  as  sulphides,  with  the  character  of 
acids,  like  realgar,  orpiment,  and  stibine ;  or  as  sulphurets, 
resembling  bases,  like  galena,  argentite,  and  pyrite.  Less 
frequent  are  haloid  salts,  with  chlorine  and  fluorine,  as 
common  salt  and  fluor  spar;  and  still  rarer  those  with 
iodine  and  bromine.  On  the  other  hand,  metallic  alloys, 
or  combinations  of  electro-negative  with  electro-positive 
metals,  are  far  from  uncommon,  especially  those  with 
arsenic,  tellurium,  or  antimony. 

Combinations  of  these  binary  compounds  with  each  other 
are  still  more  common,  the  greater  number  of  minerals 
being  composed  of  an  acid  and  base.  By  far  the  greater 
number  are  oxygen-salts,  distinguished  by  giving  to  the 
acid  the  termination  ate  ;  thu-s  sulphate  of  .lead,  silicate  of 
lime,  and  in  like  manner  numerous  carbonates,  phosphates, 
arseniates,  aluminates.  The  sulphur-salts  (two  metals  com- 
bined with  sulphur,  and  these  again  combined  with  each 
other)  are  next  in  number,  and  perform  a  most  important 
part  in  the  mineral  kingdom.  The  hydrates,  or  combina- 
tions of  an  oxide  with  water,  are  also  common,  and  much 


CHEMICAL   PROPERTIES    OF   MINERALS.  109 

resemble  the  oxygen  salts,  the  water  sometimes  acting  as 
an  electro-positive,  at  other  times  as  an  electro-negative 
element.  Combinations  of  a  higher  order  are  likewise 
common,  especially  the  double  salts,  or  the  union  of  two 
salts  into  a  new  body ;  and  even  these  again  writh  water, 
as  alum  and  many  hydrous  silicates.  The  chemical  formulas 
for  these  compound  salts  are  formed  by  writing  the  signs 
of  the  simple  salts  with  the  sign  of  addition  between  them : 
thus  Ca  C-f-'Mg  C,  i.  e.,  carbonate  of  lime  and  carbonate  of 
magnesia,  or  brown  spar ;  Al  Si3  +  K  Si3,  or  orthoclase ; 
3  Na  F  +  Al2  F3,*  or  cryolite,  composed  of  three  compound 
atoms  of  fluorine  and  sodium  united  to  one  compound  atom, 
consisting  of  three  of  fluorine  and  two  of  aluminium. 

Influence  of  the  Chemical  Composition  on  the  External 
Characters  of  Minerals. 

That  the  characters  of  the  compound  must  in  some  way 
or  other  depend  on  those  of  its  component  elements,  seems, 
as  a  general  proposition,  to  admit  of  no  doubt.  Hence  it 
might  be  supposed  possible,  from  a  knowledge  of  the  com- 
position of  a  mineral,  to  draw  conclusions  in  reference  to 
its  form  and  other  properties;  but  practically  this. has  not 
yet  been  effected'.  The  distinction  between  the  mineral- 
izing and  mineralizable,  or  the  forming  and  formed,  ele- 
ments, lies  at  the  foundation  .of  all  such  inquiries.  Certain 
elements  hi  a  compound  apparently  exert  more  than  an 
equal  share  of  influence  in  determining  its  physical  prop- 
erties. Thus  the  more  important  non-metallic  elements, 
as  oxygen,  sulphur,  chlorine,  fluorine,  are  remarkable  for 
the  influence  they  exert  on  the  character  of  the  compound. 
The  sulphurets,  for  example,  have  more  similarity  among 
themselves  than  the  various  compounds  of  one  and  the 
same  metal  with  the  non-metallic  bodies.  Still  more  gen- 


110  A  PO?ULAK  TKEATISE  ON  GEMS. 

erally  it  would  appear  that  the  electro-negative  element  in 
the  compound  is  the  most  influential,  or  exerts  the  greatest 
degree  of  active  forming  power.  After  the  non-metallic 
elements  the  brittle,  easily  fusible  metals  rank  next  in 
power;  then  the  ductile  ignoble  metals;  then  the  noble 
metals ;  then  the  brittle,  difficultly  fusible  ;  and  last  of  all, 
the  metals  of  the  earths  and  alkalies. 

It  is  sometimes  stated  that  each  particular  substance  can 
crystallize  only  in  one  particular  form  or  series  of  forms. 
This  is,  however,  only  partially  true;  and  sulphur,  for  in- 
stance, which  usually  crystallizes  in  the  rhombic  system, 
when  melted  may  form  monoclinohedric  crystals.  This 
property  is  named  dimorphism  ;  and  hence  the  same  chem- 
ical substance  may  form  two,  or  even  more  distinct  bodies 
or  mineral  species.  Thus  carbon  in  one  form  is  the  dia- 
mond, in  another  graphite ;  carbonate  of  lime  appears  as 
calc-spar  or  arragonite ;  the  bisulphuret  of  iron,  as  pyrite 
and  marcasite.  An  example  of  trimorphism  occurs  in  the 
titanic  acid,  forming  the  three  distinct  species,  anatase, 
rutile,  and  brookite.  Even  the .  temperature  at  which  a 
substance  crystallizes  -influences  its  forms,  and  so  far  its 
composition,  as  seen  in  'an-agonite,  Glauber  salt,  natron, 
and  borax. 

Still  more  important  is  the  doctrine  of  isomorphism,  des- 
ignating the  fact  that  two  or  more  simple  or  compound 
substances  crystallize  in  one  and  the  same  form  ;  or  often 
in  forms  which,  though  not  identical,  yet  approximate  very 
closely.  This  similarity  of  form  is  generally  combined  with 
a  similarity  in  other  physical  properties.  Among  minerals 
that  crystallize  in  the  tesseral  form,  isomorphism  is  of  course 
common  and  perfect,  there  being  no  diversity  in  the  dimen- 
sions of  the  primary  form ;  but  for  this  very  reason  it  is  of 
less  interest.  It  is  of  more  importance  among  mono-axial 
crystals,  the  various  series  of  which  are  separated  from  each 


CHEMICAL   PKOPERTIES   OF   MINERALS.  Ill 

other  by  differences  in  the  proportion  of  the  primary  form 
In  these,  perfect  identity  is  seldom  observed,  but  only  very 
great  similarity. 

The  more  important  isomorphic  substances  are  the  fol- 
lowing : 

I.  Simple  substances : 

(l.)  Fluorine  and  chlorine. 

(2.)  Sulphur  and  selenium. 

(3.)  Arsenic,  antimony,  tellurium. 

(4.)  Cobalt,  iron,  nickel. 

(5.)  Copper,  silver,  quicksilver,  gold  (?). 

II.  Combinations  with  oxygen  : 
(1.)  Of  the  formula  B. 

(a.)  Lime,  magnesia,  protoxide  of  iron,  protoxide 
of  manganese,  oxide  of  zinc,  oxide   of  nickel, 
oxide  of  cobalt,  potassa,  soda. 
(b.)  Lime,  baryta,  strontia,  lead-oxide. 
(2.)  Of  the  formula  S. 

(a.)  Alumina,  peroxide  of  iron,  peroxide  of  manga- 
nese, oxide  of  chromium. 
(b.)  Antimony  oxide,  arsenious  acid. 
(3.)  Formula  R.     Tin-oxide,  titanium-oxide. 

(4.)  Formula  R.    Phosphoric  acid,  arsenic  acid. 
(5.)  Formula  R. 

(a.)  Sulphuric  acid,.selenic  acid,  chromic  acid,  man- 
ganese acid. 

(b.)  Tungstic  acid,  molybdic  acid. 
HI.  Combinations  with  sulphur : 

(1.)  Formula  Rf.     Sulphuret  of  iron  Fe',  and  sulphu- 

ret  of  zinc  Zn'. 
(2.)  Formula  ft'".     Sulphuret  of^antimony  Sb'1',  and 

sulphuret  of  Arsenic  As'".      • 
(3.)  Formula -R'.     Sulphuret  of  copper -0u',  and  sul- 

phuret  of  silver  Ag'. 


112  A  POPULAR  TREATISE  ON  GEMS. 

These  substances  are  named  vicarious,  from  the  singular 
property  that  in  chemical  compounds  they  can  mutually 
replace  each  other  in  indefinite  proportions,  and  very  often 
without  producing  any  important  change  in  the  form  or 
other  physical  properties.  But  there  are  numerous  in- 
stances among  the  silicates,  where  the  mutual  replacement 
of  the  isomorphic  bodies,  especially  when  the  oxides  of  the 
heavy  metals  come  in  the  room  of  the  earths  and  alkalies, 
exerts  a  most  essential  influence  on  the  external  aspect  oi 
the  species,  particularly  in  regard  to  color,  specific  gravity, 
and  transparency.  The  varieties  of  hornblende,  augite, 
garnet,  epidote,  and  many  other  minerals,  are  remarkable 
proofs  of  this  influence.  This  intermixture  *of  isomorphic 
elements  confers  many  valuable  properties  on  minerals,  and 
.to  it  this  department  of  nature  owes  much  of  its  variety  and 
beauty.  Without  the  occasional  presence  of  the  coloring 
substances,  especially  the  oxides .  of  iron  and  manganese, 
the  non-metallic  combinations  would  have  exhibited  a  very 
monotonous  aspect.  It  is  also  remarkable,  that  in  some 
silicates  the  substitution  of  a  certain  portion  of  the  metallic 
oxides  for  the  earthy  bases  seems  to  be  almost  a  regular 
occurrence;  while  in  others,  as  the  felspars  and  zeolites, 
this  rarely  happens.  This  fact  is  of  very  great  economic 
importance,  as  drawing  attention  to  important  elements 
often  combined  with  others  of  less  value.  Thus  iron  oxide 
and  chrome  oxide,  sulphuret  of  copper  and  sulphuret  of 
silver,  nickel  and  cobalt,  may  be  looked  for  in  connection. 
The  general  chemical  formula  for  such  compounds  is  formed 
by  writing  R  (= radicle  or  basis)  for  the  whole  isomorphic 
elements;  and  in  special  instances  to  place  their  signs 
either  one  below  the  other,  connected  by  a  bracket,  or,  as 
is  more  convenient,  to  inclose  them  in  brackets  one  after 
the  other,  separated  by  a  comma.  Thus  the  general  sign 
for  the  garnet  is  R3  Si2+R  Si,  which,  wThen  fully  expressed. 


CHEMICAL   PROPERTIES    OF    MINERALS.  113 


•;-, 
becomes  Fe1  1  Si'+^-   [  Si;  or(Ca!,Fe3,Mn3)Si'+(Al,¥e)Si, 

fin'} 
and  the  mineral  forms  many  varieties,  as  the  one  or  other 

element  predominates. 


Chemical  Reaction  of  Minerals. 

The  object  pf  the  chemical  examination  of  minerals  is 
the  discovery  of  those  elementary  substances  of  which  the  j 
consist.  This  examination  is  named  qualitative  when  the 
nature  of  the  elements  alone,  quantitative  when  also  their 
relative  amount,  is  sought  to  be  determined.  Mineralogists 
are  in  general  content  with  such  an  examination  as  will 
discover  the  more  important  elements,  and  which  can  be 
carried  on  with  a  simple  apparatus,  and  small  quantities  of 
the  substance  investigated.  The  indications  thus  furnished 
of  the  true  character  of  the  mineral  are,  however,  frequently 
of  high  importance.  Two  methods  of  testing  minerals  are 
employed,  the  one  by  heat  chiefly  applied  through  the  blow- 
pipe, the  second  by  acids  and  other  reagents  in  solution. 

Use  of  the  Blowpipe- 

The  blowpipe  in  its  simplest  form  is  merely  a  conical 
tube  of  brass  or  othei*  metal,  curved  round  at  the  smaller 
extremity,  and  terminating  in  a  minute  circular  aperture 
not  larger  than  a  fine  needle.  Other  forms  have  been 
proposed,  one  of  the"  most  useful  being  a  cone  of  tin,  open 
for  the  application  of  the  mouth  at  the  smaller  end,  and 
with  a  brass  or  platina  beak  projecting  from  the  side  near 
the  other  or  broad  end.  With  this  instrument  a  stream  of 
air  is  conveyed  from  the  mouth  to  the  flame  of  a  lamp  or 
candle,  so  that  this  can  be  turned  aside,  concentrated,  and 


114  A   POPULAR   TREATISE   ON   GEMS. 

directed  upon  any  small  object.  The  flame  thus  acted  on 
consists  of  two  parts — the  one  nearest  the  beak  of  the  blow- 
pipe forming  a  blue  obscure  cone,  the  other  external  to  this 
being  of  a  shining  yellow  or  reddish-yellow  color.  The 
blue  cone  consists  of  the  inflammable  gases  not  yet  fully 
incandescent,  and  the  greatest  heat  is  just  beyond  its  point, 
where  this  is  fully  effected.  The  blue  flame  still  needs 
oxygen  for  its  support,  and  consequently  tends  to  withdraw 
it  from  any  body  placed  within  its  influence,  and  is  named 
the  reducing  flame.  At  the  extremity  of  the  yellow  cone, 
on  the  other  hand,  the  whole  gases  being  consumed  and 
the  external  air  having  free  access,  bodies  are  combined 
with  oxygen,  and  this  part  is  named  the  oxidating  flame. 
Their  action  being  so  distinct,  it  is  of  great  importance  for 
the  student  to  learn  to  distinguish  accurately  these  two 
portions  of  the  flame.  This  is  best  done  by  experimenting 
on  a  piece  of  metallic  tin,  which  can  only  be  kept  pure  in  a 
good  reducing  flame,  and  acquires  a  white  crust  when  acted 
on  by  the  oxidating  flame. 

The  portion  of  the  mineral  to  be  examined  should  not 
be  larger  than  a  peppercorn,  or  a  fine  splinter  a  line  or  two 
long.  It  is  supported  in  the  flame  either  by  a  pair  of  fine 
pincers  pointed  with  platinum,  or  on  slips  of  platinum-foil, 
or  on  charcoal.  Platinum  is  best  for  the  siliceous  minerals, 
whereas  for  metallic  substances  charcoal  must  be  employed. 
For  this  purpose  solid  uniform  pieces  are  chosen,  and  a 
small  cavity  formed  in  the  surface  in  which  the  mineral  to 
be  tested  can  be  deposited. 

In  examining  a  mineral  by  heat,  it  should  be  first  tested 
alone,  and  then  with  various  reagents.  When  placed  alone 
in  a  matrass  or  tube  of  glass  closed  at  one  end,  and  heated 
over  a  spirit-lamp,  water  or  other  volatile  ingredients,  mer- 
cury, arsenic,  tellurium,  often  sulphur,  may  readily  be  de- 
tected, being  deposited  in  the  cooler  part  of  the  tube,  or, 


CHEMICAL   PROPERTIES    OF   MINERALS.  115 

like  fluorine,  acting  on  the  glass.  It  may  next  be  tried  in 
an  open  tube  of  glass,  through  which  a  more  or  less  strong 
current  of  air  passes  according  to  the  inclination  at  which 
the  tube  is  held,  so  that  volatile  oxides  or  acids  may  be 
formed ;  and  in  this  way  the  chief  combinations  of  sulphur, 
selenium,  tellurium,  and  arsenic  are  detected.  On  char- 
coal, in  the  reducing  flame,  arsenic,  and  in  the  oxidating 
flame,  selenium  or  sulphur,  are  shown  by  their  peculiar 
odor ;  antimony,  zinc,  lead,  and  bismuth  leave  a  mark  or 
colored  ring  on  the  charcoal ;  and  other  oxides  and  sul- 
phurets  are  reduced  to  the  pure  metal.  On  charcoal  or  in 
the  platinum  pincers  the  fusibility  of  minerals  is  tested,  and 
some  other  phenomena  should  be  observed — as  whether 
they  intumesce  (bubble  up),  effervesce,  give  out  fumes,  be- 
come shining,  or  impart  a  color  to  the  flame.  The  color  is 
seen  when  the  assay  is  heated  at  the  point  of  the  inner 
flame,  and  is — 

Reddish-yellow,  from  soda  and  its'salts  ;  9 

Violet,  from  potash  and  most  of  its  salts  ; 

Red,  from  litliia,  strontia,  and  lime  ; 

Green,   from   baryta,   phosphoric  acid,   boracic  acid,  molybdic  acid, 

copper  oxide,  and  tellurium  oxide  ;. 
Blue,  from  chloride  of  copper,  bromide  of  copper,  selenium,  arsenic, 

antimony,  and  lead. 

The  fusibility,  or  ease  with  which  a  mineral  is  melted, 
should  also  be  observed;  and  to  render  this  character  more 
precise,  Yon  Kobell  has  proposed  this  scale: — (l.)  Anti- 
mony glance,  which  melts  readily  in  the  mere  candle  flame ; 
(2.)  Xatrolite,  which  in  fine  needles  also  melts  in  the  candle 
flame,  and  in  large  pieces  readily  before  the  blowpipe ;  (3.) 
Almandine  (garnet  from  Zillerthal),  which  does  not  melt 
in  the  candle  flame  even  in  fine  splinters,  but  in  large  pieces 
before  the  blowpipe ;  (4.)  Strahlstein  (hornblende  from 
Zillerthal)  melts  with  some  difficulty,  but  still  more  readily 
than  (5.)  Orthoclase  (or  adularia  felspar) ;  and  (6.)  Bron- 


116  A  POPULAR  TREATISE  ON  GEMS. 

zite  or  diallage,  of  which  only  the  finest  fibres  can  be 
rounded  by  the  blowpipe.  In  employing  this  scale,  fine 
fragments  of  the  test  minerals  and  of  that  to  be  tried,  and 
nearly  of  equal  size,  should  be  exposed  at  the  same  time  to 
the  flame.  A  more  common  mode  of  expressing  fusibility 
is  to  state  whether  it  is  observable  in  large  or  small  grains, 
in  fine  splinters,  or  only  on  sharp  angles.  The  result  or 
product  of  fusion  also  yields  important  characters,  being 
sometimes  a  glass,  clear,  opaque,  or  colored ;  at  other  times 
an  enamel,  or  a  mere  slag. 

The  most  important  reagents  for  testing  minerals  with 
the  blowpipe  are  the  following:  (1.)  Soda  (the  carbonate), 
acting  as  a  flux  for  quartz  and  many  silicates,  and  especially 
for  reducing  the  metallic  oxides.  For  the'  latter  purpose, 
the  assay  (or  mineral  to  be  tried)  is  reduced  to  powder, 
kneaded  up  with  moist  soda  into  a  small  ball,  and  placed 
in  a  cavity  of  the  charcoal.  Very  often  both  the  soda  and 
assa^  sink  into  the  charcoal, 'but  by  continuing  the  opera- 
tion they  either  again  appear  on  the  surface,  or,  when  it  is 
completed,  the  charcoal  containing  the  mass  is  finely  pounded 
and  washed  away  with  water,  when  the  reduced  metal  is 
found  in  the  bottom  of  the  vessel.  (2.)  Borax  (biborate  of 
soda)  serves  as  a  flux  for  many  minerals,  which  are  best, 
fused  in- small  splinters  on  platina  wire.  The  borax  when 
first  exposed  to  the  flame  swells  up  or  intumesces  greatly, 
and  it  should  therefore  be  first  melted  into  a  small  bead,  in 
which  the  assay  is  placed.  During  the  process  the  student 
should  observe  whether  the  assay  melts  easily  or  difficultly, 
with  or  without  effervescence,  what  color  it  .imparts  to  the 
product  both  when  warm  and  when  cold,  and  also  the  effect 
both  of  the  oxidating  and  reducing  flames.  (3.)  Microcos- 
mic  salt,  or  salt  of  phosphorus  (phosphate  of  soda  and  am- 
monia), is  specially  important  as  a  test  for  metallic  oxides, 
which  exhibit  far  more  decided  colors  with  it  than  with 


CHEMICAL    PROPERTIES    OP    MINERALS.  117 

borax.  It  is  also  a  useful  reagent  for  many  silicates,  whose 
silica  is  separated  from  the  base  and  feraains  undissolved 
in  the  melted  salt.  (4.)  Solution  of  cobalt  (nitrate  of  co- 
balt dissolved  in  water),  or  dry  oxalate  of  cobalt,  serve  as 
tests  of  alumina,  magnesia,  and  zinc  oxide. 

In  examining  minerals  in  th*e  moist  way,  the  first  point 
to  be  considered  is  their  solubility,  of  which  three  .degrees 
may  be  noted :  (!)•  minerals  soluble  in  water ;  (2)  minerals 
soluble  in  hydrochloric  or  nitric  acid;  and  (3)  those  un- 
affected by  any  of  these  fluids.  The  minerals  soluble  in 
water  are  either  acids  (almost  only  the  boracic  acid  or  sas- 
solin  and  the  arsenious  acid),  or  oxygen  or  haloid  salts. 
These  are  easily  tested,  one  part  of  the  solution  being  em- 
ployed to  find  the  electro-positive  element  or  basis,  the 
other  the  electro-negative  or  acid. 

Minerals  insoluble  in  water  may  next  be  tested  with  the 
above  acids;  the  nitric  acid  being  preferable  when  it  is 
probable,  from  the  aspect  of  the  mineral  or  its  conduct  be- 
fore the  blowpipe,  that  it  contains  an  alloy,  a  sulphuret, 
or  arseniate  of  some  metal.  In  this  manner  the  carbonic, 
phosphoric,  arsenic,  and  chromic  acid  salts,  many  hydrous 
and  anhydrous  silicates,  many  sulphurets,  arseniates,  and 
other  metallic  compounds,  are*  dissolved,  so  that  further 
tests  may  be  employed. 

The  minerals  insoluble  either  in  water  or  these  acids  are" 
sulphur,  graphite,  cinnabar,  some  metallic  oxides,  some 
sulphates,  and  compounds  with  chlorine  and  fluorine,  and 
especially  quartz,  and  various  silicates.  For  many  of  these 
no  test  is  required,  or  those  furnished  by  the  blowpipe  are 
sufficient.  The  silicates  and  others  may  be  fused  with  four 
times  their  weight  of  anhydrous  carbonate  of  soda  when 
they  are  rendered  soluble,  so  that  further  tests  may  be  ap- 
plied. 


118          A  POPULAR  TREATISE  ON  GEMS. 

Chemical  Reaction  of  the,  more  Important  Element*. 

It  is  not  intended  in  this  place  to  describe  the  chemical 
nature  of  the  elementary  substances,  and  still  less  to  enu- 
merate the  whole  of  those  marks  by  which  the  chemist  can 

•  •  * 

detect  their  presence.  Our  object  is  limited  principally  to 
the  conduct  of  minerals  before  the  blowpipe,  and  to  a  few 
simple  tests  by  which  their  more  imp'ortant  constituents 
may  be  discovered  by  the  student. 

I. — NON-METALLIC   ELEMENTS,    AND   THEIR   COMBINATIONS 
WITH    OXYGEN. 

Nitric  Acid. — Most  of  its  salts  detonate  when  heated  on 
charcoal.  In  the  closed  tube  they  form  nitrous  acid>  easily 
known  by  its  orange  color  and  smell ;  a  test  more  clearly 
exhibited  when  the  salt  is  mixed  with  copper  filings  and 
treated  with  concentrated  sulphuric  acid.  When  to  the 
solution  of  a  nitrate,  a  fourth  part  of  sulphuric  acid,  is  added, 
and  a  fragment  of  green  vitriol  placed  in  it,  the  surround- 
ing fluid  becomes  of  a  dark-brown  color. 

Sulphur  and  its  compounds,  in  .the  glass  tube  or  on  char- 
coal, form  sulphurous  acid,"  easily  known  by  its  smell.  The 
minutest  amount  of  sulphur  or  sulphuric  acid  may  be  de- 
tected by  melting  the  pulverized  assay  with  two  parts  soda 
and  one  part  borax,  and  placing  the  bead  moistened  with 
water  on  a  plate  of  clean  silver,  which  is  then  stained  brown 
or  black.  Solutions  of  sulphuric  acid  give  with  chloride  of 
barium  a  heavy  white  precipitate,  insoluble  in  acids. 

Phosphoric  Acid. — Most  combinations  with  this  acid 
tinge  the  blowpipe  flame  green,  especially  if  previously 
moistened  with  sulphuric  acid.  The  experiment  must  be 
performed  in  the  dark,,  when  even  three  per  cent,  of  the 
acid  may  be  detected.  If  the  assay  is  melted  with  six  parts 


CHEMICAL   PROPERTIES    OF   MINERALS.  119 

of  soda,  digested  in  water,  filtered,  and  neutralized  with 
acetic  acid,  the  solution  forms  an  orange-yellow  layer  round 
a  crystal  of  nitrate  of  silver.  This  solution,  with  muriate 
of  magnesia,  forms  a  white  crystalline  precipitate. 

Selenium  and  Setenic  Add  are  readily  detected  by  the 
strong  smell  of  decayed  horse-radish,  and  leave  a  gray  de- 
posit with  a  metallic  lustre  on  the  charcoal. 

Chlorine  and  Hs  salts.  When  oxide  of  copper  is  melted 
with  salt  of  phosphorus  into  a  very  dark-green  bead,  and 
an  assay  containing  chlorine  fused  with  this,  the  flame  is 
tinged  of  a  beautiful  reddish-blue  color,  till  all  the  chlorine 
is  driven  off.  If  very  little  chlorine  is  present,  the  assay  is 
dissolved  in  nitric  acid  (if  not  soluble  it  must  first  be  melted 
with  soda  on  platinum  wire),  and  the  diluted  solution  gives, 
with  nitrate  of  silver,  a  precipitate  of  chloride  of  silver, 
which  is  first  white,  but  on  exposure  to  the  light  becomes 
gradually  brown,  and  at  length  black. 

Iodine  and  its  salts,  treated  like  chlorine,  impart  a  very 
beautiful  bright-green  color  to  the  flame ;  and  heated  in 
the  closed  tube  with  sulphate  of  potash,  yield  violet-colored 
vapors.  In  solution  it  gives,  with  nitrate  of  silver,  a  pre- 
cipitate similar  to  chlorine,  but  which -is  very  difficultly 
soluble  in  ammonia.  Its  surest  test  is  the  blue  color  it  im- 
parts to  starch,  best  seen,  by  pouring  concentrated  sul- 
phuric acid  over  the  mineral  in  a  test  tube  which  has  a 
piece  of  paper  or  cotton  covered  with  moist  starch  over  its 
mouth. 

Bromine  and  its  salts,  treated  in  the  same  manner  with 
salt  of  phosphorus  and  oxide  of  copper,  color  the  blowpipe 
flame  greenish-blue.  In  the  closed  tube  with  nitrate  of 
potassa  they  yield  bromine  vapors,  known  by  their  yellow 
color  and  peculiar  disagreeable  smell.  Treated  with  "sul- 
phuric acid,  bromine  in  a  few  hours  colors  starch  pome- 
granate-yellow. 


120          A  POPULAR  TREATISE  ON  GEMS. 

Fluorine  is  shown  by  heating  the  assay  with  sulphate  of 
potassa,  in  a  closed  tube  with  a  .strip  of  logwood-paper  in 
the  open  end.  The  paper  becomes  straw-yellow,  and  the 
glass  is  corroded.  Another  test  is  to  heat  the  pulverized 
mineral  with  concentrated  sulphuric  acid  in  a  shallow  dish 
of  platinum  (or  lead),  over  which  a  plate  of  glass  covered 
with  a  coat  of  wax,  through  which  lines  have,  been  drawn 
with  a  piece  of  sharp-pointed  wood,  is  placed.  If  fluorine 
is  present,  the  glass  is  etched  where  exposed. 

JBoracic  Acid. — The  mineral  alone,  or  moistened  with 
sulphuric  acid,  when  melting,  colors  the  flame  momentarily 
green.  If  the  assay  be  heated  with  sulphuric  acid,  and 
alcohol  added  and  set  on  fire,  the  flame  is  colored  green 
from  the  vapors  of  the  boracic  acid. 

Carbon,  pulverized  and  heated  with  saltpetre,  detonates, 
leaving  carbonate  of  potassa.  Carbonic  acid  is  not  easily 
discovered  with  the  blowpipe,  but  the  minerals  containing 
it  effervesce  in  hydrochloric  acid,  and  the  colorless  gas 
that  escapes  renders  litmus-paper  red.  In  solution  it  forms 
a  precipitate  with  lime-water,  which  is  again  dissolved  with 
effervescence  in  acids. 

Silica,  before  the  blowpipe,  alone  is  unchanged  ;  is  very 
slowly  acted  on  by  borax,  very  little  by  salt  of  phosphorus, 
but  with  soda  melts  entirely  with  a  brisk  effervescence  into 
a  clear  glass.  The  silicates  are  decomposed  by  salt  of 
phosphorus,  the  silica  being  left  in  the  bead  as  a  powder 
or  a  skeleton.  Most  of  them  melt  with  soda  to  a  trans- 
parent glass.  .Some  silicates  are  dissolved  in  hydrochloric 
acid,  and  this  the  more  readily  the  more  powerful  the 
basis,  the  less  proportion  of  silica,  and  the  greater  the 
amount  of  water  they  contain.  Sometimes  the  acid  only 
extracts  the  basis,  leaving  the  silica  as  a  powder  or  jelly ; 
or  the  silica  too  is  dissolved,  and  only  gelatinizes  on  evapo- 
ration. The  insoluble  silicates  may  be  first  melted  with 


CHEMICAL   PROPERTIES    OF   MINERALS.  121 

some  carbonate  of  an  alkali*,  when  the  solution  gelatinizes, 
and  finally  leaves  a  dry  residuum,  of  which  the  part  insolu- 
ble in  warm  hydrochloric  acid  has  all  the  properties  of 
silica. 

n. THE  ALKALIES  AXD  EARTHS. 

Ammonia,  heated  with  soda  in  a  closed  tube,  is  readily 
known  by  its  smell.  Its  salts,  heated  with  solution  of 
potassa,  also  yield  the  vapor,  known  from  its  smell,  its 
action  on  turmeric-paper,  and  the  white  fumes  that  rise 
from  a  glass  tube  dipped  in  hydrochloric  acid  held  over  it. 

Soda,  imparts  a  reddish-yellow  color  to  the  external 
flame  when  the  assay  is  fused  or  kept  at  a  strong  red  heat. 
In  solution  it  yields  no  precipitate  with  chloride  of  plati- 
num or  sulphate  of  alumina. 

Lithia  is  best  recognized  by  the  beautiful  carmine-red 
color  it  imparts  to  the  flame  during  the  fusion  of  a  mineral 
containing  it  in  considerable  amount.  Where  the  propor- 
tion is  small,  the  color  appears  if  the  assay  be  mixed  with 
1  part  fluor  spar  and  1^  parts  sulphate  of  potassa.  In 
concentrated  solutions  it  forms  a  precipitate  with  the  phos- 
phate and  carbonate  of  soda,  but  none  with  bichloride  ol 
platinum,  sulphate  of  alumina,  or  acetic  acid. 

Potassa  gives  a  violet  color  to  the  external  cone,'  when 
th^assay  is  heated  at  the  extremity  of  the  oxidating  flame. 
The  presence  of  lithia  or  soda,  however,  disturbs  this  re- 
.action.  It  may  still  be  discovered  by  melting  the  assay  in 
borax  glass  colored  brown  by  nickel  oxide,  which '  is 
changed  to  blue  by  the  potassa.  In  concentrated  solutions 
of  potassa,  the  bichloride  of  platinum  gives  a  citron-yellow 
precipitate ;  acetic  acid,  a  white  granular  precipitate ;  and 
sulphate  of  alumina,  after  some  time,  a  deposit  of  alum-' 
crystals. 

Baryta. — The  carbonate  of  this  earth  melts  easily  to  a 
6 


122  A   POPULAR   TREATISE   ON   GEMS. 

clear  glass,  milk-white  when  cold;  the  sulphate  is  very 
difficultly  fusible.  Both  strongly  heated  at  the  point  of 
the  blue  flame  impart  a  green  tinge  to  the  outer  flame. 
When  combined  with  silica  it  cannot  be  well  discovered  by 
the  blowpipe.  In  solution,  salts  of  baryta  yield,  with  sul- 
phuric acid  or  solution  of  sulphate  of  lime,  immediately  a 
fine  white  precipitate  insoluble  in  acids  or  alkalies. 

Strontia,  the  carbonate,  even  in  thin  plates,  only  melts 
on  the  edges,  and  forms  cauliflower-like  projections  of 
dazzling  brightness ;  the  sulphate  melts  easily  in  the  oxi- 
dating flame,  and  in  the  reducing  flame  is  changed  into 
sulphuret  of  strontium,  which,  dissolved  in  hydrochloric 
acid,  and  evaporated  to  dryness,  gives  a  fine  carmine-red 
color  to  the  flame  of  alcohol.  Strontia  in  solution  gives 
a  precipitate  with  sulphuric-  acid,  or  with  sulphate  of  lime, 
but  not  immediately. 

Lime. — The  carbonate  is  rendered  caustic  by  heat,  when 
it  has  alkaline  properties,  and  readily  absorbs  water.  The 
sulphate  in  the  reducing  flame  changes  to  the  sulphuret 
of  calcium,  which  is  also  alkaline.  Sulphuric  acid  precipi- 
tates lime  only  from  very  concentrated  solutions;  oxalic 
acid  even  from  very  weak  ones ;  and  silico-hydrofluoric  acid 
not  at  all.  As  baryta  and  strontia  also  form  precipitates 
with  the  first  two  reagents,  they  must  previously  be  sepa- 
rated by  sulphate  of  potassa.  Chloride  of  calcium  tinges 
the  flame  of  alcohol  yellowish-red. 

Magnesia,  alone,  or  as  a  hydrate,  a  carbonate,  and  in 
some  other  combinations,  when  ignited  with  solution  of 
cobalt,  or  the  oxalate  of  cobalt,  assumes  a  light-red  tint. 
It  is  not  precipitated  from  a  solution  either  by  sulphuric 
acid,  oxalic  acid,  or  silico-hydrofluoric  acid ;  but  phosphoric 
acid,  with  ammonia,  throws  down  a  white  crystalline  pre- 
cipitate of  phosphate  of  ammonia  and  magnesia. 

Alumina  alone  is  infusible.   In  many  combinations,  when 


CHEMICAL   PBOPERTTES   OF   MINERALS.  123 

ignited  with  solution  of  cobalt,  it  assumes  a  fine  blue  color. 
It  is  thrown  down  by  potassa  or  soda  as  a  white  volumin- 
ous precipitate,  which  in  excess  of  the  alkali  is  easily  and 
completely  soluble,  but  is  again  precipitated  by  muriate  of 
ammonia.  Carbonate  of  ammonia  also  produces  a  precipi- 
tate which  is  not  soluble  in  excess. 

Glucina,  Yttria,  Zirconia,  and  Thorina  are  not  prop- 
erly distinguished  by  blowpipe  tests,  though  the  minerals 
in  which  they  occur  are  well  marked  in  this  way.  In 
solution,  glucina  acts  with  potassa  like  alumina ;  but  the 
precipitate  with  carbonate  of  ammonia .  is  again  soluble, 
with  excess  of  the  alkali,  and  the  two  earths  may  thus  be 
separated.  Yttria  is  precipitated  by  potassa,  but  is  not 
again  dissolved  by  excess  of  the  alkali.  With  carbonate 
of  ammonia  it  acts  like  glucina.  It  must  be  observed, 
however,  that  the  substance  formerly  named  yttria  is  now 
considered  a  mixture  of  this  earth  with  the  oxides  of  er- 
bium, terbium,  and  lanthanium.  Zirconia  acts  with  potassa 
like  yttria,  and  with  carbonate  of  ammonia  like  glucina. 
Concentrated  sulphate  of  potassa  throws  down  a  double  salt 
of  zirconia  and  potassa,  which  is  very  little  soluble  in  pure 
water. 

III. THE   METALS. 

Arsenic  and  its  sulphuret  on  cha/coal  yield  fumes,  with 
a  smell  like  garlic,  and  sublime  in  the  closed  tube.  The 
greater  number  of  alloys-  of  arsenic  in  the  reducing  flame 
leave  a  white  deposit  on .  the  charcoal ;  or,  where  it  is  in 
larger  proportion,  give  out  grayish-white  fumes  with  a 
smell  of  garlic.  Some  alloys  'also  yield  metallic  arsenic  in 
the  closed  tube.  In  the  open  tube  all  of  them  yield  ar.se- 
nious  acid,  and  those  containing  sulphur  also  sulphurous 
fumes.  Many  arsenic  acid  salts  emit  evident  odors  of 
arsenic  when  heated  on  charcoal  with  soda ;  and  some  sub- 


124  A  POPULAR  TREATISE  ON  GEMS. 

lime  metallic  arsenic  when  heated  with  pulverized  charcoal 
in  the  closed  tube. 

Antimony  melts  easily  on  charcoal,  emitting  dense  white 
fumes,  and  leaving  a  ring  of  white  crystalline  oxide  on  the 
support.  In  the  closed  tube  it  does  not  sublime,  but  burns 
in  the  open  tube  with  white  smoke,  leaving  a  sublimate  on 
the  glass,  which  is  easily  driven  from  place  to  place  by  heat. 
Most  of  its  compounds,  with  sulphur  or  "with  the  other 
metals,  show  similar  reaction.  Antimony  oxide  on  char- 
coal melts  easily,  fumes,  and  is  reduced,  coloring  the  flame 
pale  greenish-blue.. 

Bismuth  melts  easily,  fumes,  and  leaves  a  yellow  oxide 
on  the  charcoal.  In  the  closed  tube  it  does  not  sublime, 
and  in  the  open  tube  scarcely  fumes,  but  is  surrounded  by 
the  fused  oxide,  dark-brown  when  warm,  and  bright-yellow 
when  cold.  Its  oxides  are  easily  reduced.  A  great  addi- 
tion of  water  produces  a  white  precipitate  from  its  solution 
in  nitric  acid.  . 

Tellurium  fumes  on  charcoal,  and  becomes  surrounded 
by  a  white  mark  with  a  reddish  border,  which,  when  the 
reducing  flame  is  turned  on  it,  disappears  with  a  bluish- 
green  light.  In  the  closed  tube  tellurium  gives  a  subli- 
mate of  the  gray  metal ;  and  in  the  open  tube  produces 
copious  fumes,  and  a  white  powder  which  can  be  melted 
into  small  clear  drops.  . 

Mercury  in  all  its  combinations  is  volatile,  and  yields  a 
metallic  sublimate  when  heated  alone,  or  with  tin  or  soda 
in  the  closed  tube. 

Zinc,  when  heated  with  soda  on  charcoal,  forms  a  de- 
posit, which>  when  warm,  is  yellow;  when  cold,  white  ;  is 
tinged  of  a  fine  green  by  solution  of  cobalt,  and  is  not  fur- 
ther volatile  in  the  oxidating  flame.  In  solution,  zinc  is 
precipitated  by  potassa  as  a  white  gelatinous  hydrate,  easily 
redissolved  in  the  excess  of  the  alkali. 


CHEMICAL   PROPERTIES    OF    MINERALS.  125 

Tin  forms  a  white  deposit  on  the  charcoal  behind  the 
assay,  which  takes  a  bluish-green  color  with  the  solution  oi 
cobalt.  The  oxide  is  easily  reduced  by  soda. 

-LeadTorms  a  sulphur-yellow  deposit  with  a  white  border 
on  the  charcoal  when  heated  in  the  oxidating  flame,  and 
with  soda  is  easily  reduced.  The  solutions  of  its  salts  are 
colorless,  but  give  a  black  precipitate  with  sulphuretted 
hydrogen ;  with  sulphuric  acid  a  white,  and  with  chromate 
of  potassa  a  yellow,  precipitate. 

Cadmium  produces,  with  soda,  a  reddish-brown  or 
orange-yellow  ring,  with  iridescent  border  on  the  charcoal, 
and  also  on  platinum-foil. 

Manganese  alone,  melted  with  borax  or  salt  of  phos- 
phorus on  the  platinum  wire  in  the  oxidating  flame,  forms 
a  fine  amethystine  glass,  which  becomes  colorless  in  the 
reducing  flame.  In  combination  with  other  metals,  the 
pulverized  assay  mixed  with  two  or  three  times  as  much 
soda,  and  melted  in  the  oxidating  flame  on  platinum-foil, 
forms  a  bluish-green  glass.  Potassa  or  ammonia  throws 
down  from  solutions  of  its  salts  a  white  hydrate,  which,  in 
the  air,  becomes  gradually  dark-brown. 

Cobalt,  melted  with  borax  in  the  oxidating  flame,  gives 
a  beautiful  blue  glass.  Minerals  of  metallic  aspect  must  be 
first  roasted  on  charcoal.  The  salts  of  protoxide  of  cobalt 
form  bright-red  solutions,  from  which  potassa  throws  down 
a  blue  flaky  hydrate,  which  becomes  olive-green  hi  the  air. 

Nickel,  the  assay,  first  roasted  in  the  open  tube  and  on 
charcoal,  produces  in  the  oxidating  flame,  with  borax,  a 
glass,  which  hot,  is  reddish  or  violet  brown ;  when  cold, 
yellowish  or  dark  red ;  and  by  the  addition  of  saltpetre, 
changes"  to  blue.  In  the  reducing  flame  the  glass  appears 
gray.  With  salt  of  phosphorus  the  reaction  is  similar,  but 
the  glass  is  almost  colorless  when  cold.  The  salts  in  solu- 
tion have  a  bright-green  color,  and  with  potassa,  form  a 


126  A  POPULAR  TREATISE  ON  GEMS. 

green  precipitate  of  liydrated  nickel-oxide,  which  is  un- 
changed in  the  air. 

Copper  may  in  most  cases  be  discovered  by  melting 
the  assay  (if  apparently  metallic,  first  roasted)  wifh  borax 
or  salt  of  phosphorus  in  the  oxidating  flame,  when  an 
opaque  recldish-brown  glass  is  produced,  a  small  addition 
of  tin  aiding  in  the  result.  In  the  reducing  flame,  the  glass, 
when  warm,  is  green ;  when  cold,  blue.  With  soda,  me- 
tallic copper  is  produced.  A  small  proportion  of  copper 
may  often  be  detected"  by  heating  the  assay,  moistened 
with  hydrochloric  acid,  in  the  oxidating  flame,  which  is 
then  tinged  of  a  beautiful  green  color.  Solutions  of  its 
salts  are  blue  or  green,  and  produce  a  brownisliTblack  pre- 
cipitate, with  sulphuretted  hydrogen.  Ammonia  at  first 
throws  down  a  pale-green  or  blue  precipitate,  but  in  excess 
produces  a  very  fine  blue  color.  t 

Silver  in  the  metallic  state  is  at  once  known,  and  from 
many  combinations  can  be  readily  extracted  on  charcoal 
with  soda.  From  its  solution  in  nitric  acid,  silver  is  thrown 
down  by  hydrochloric  acid  as  a  white  chloride,  which  in 
the  light  soon  becomes  black,  is"  soluble  in  ammonia,  and 
can  again  be  precipitated  from  this  solution  by  nitric  acid 
as  chloride  of  silver. 

Gold,  when  pure,  is  readily  known,  and  is  easily  separated 
'from  its  combinations  with  tellurium  on  charcoal.  If  the 
grain  is  white,  it  contains  more  silver  than  gold,  and  must 
then  be  heated  in  a  porcelain  capsule  with  nitric  acid,  which 
gives  it  a  Wack  color,  and  gradually  removes  the  silver,  if 
the  gold  is  only  a  fourth  part  or  less.  If  the  proportion  of 
gold  is  greater,  the  nitro-chloric  acid  must  be  used,  which 
then  removes  the  gold.  From  its  solution  in  this  acid  the 
protochloride  of  tin  throws  down  a  purple  precipitate  (pur- 
ple of  Cassius),  and  the  sulphate  of  iron,  metallic  gold. 

Platinum,  and  the  metals  usually  found  with  it,  cannot 


CHEMICAL  PROPERTIES  OF  MINERALS.        127 

be  separated  from  each  other  by  heat.  Only  the  Osmium- 
iridium  strongly  heated  in  the  closed  tube  with  saltpetre 
is  decomposed,  forming  osmium  acid,  known  from  its  pecu- 
liar pungent  odor.  The  usual  mixture  of  platinum  grains 
is  soluble  in  nitro-chloric  acid,  leaving  osmium-iridium. 
From  this  solution'  the  platinum  is  thrown  down  by  sal- 
ammonia  as  a  double  chloride  of  platinum  and  ammonium. 
From  the  solution  evaporated,  and  again  diluted,  with 
cyanide  of  mercury,  the  palladium  separates  as  cyanide  of 
palladium.  The  rhodium  may  be  separated  by  its  property 
of  combining  with  fused  bisulphate  of  potassa,  which  is  not 
the  case  with  platinum  or  iridium. 

Cerium,  when  no  iron-oxide  is  present,  produces,  with 
borax  and  salt  of  phosphorus,  in  the  oxidating  flame,  a  red 
or  dark-yellow  glass,  which  becomes  very  pale  when  cold, 
and  colorless  in  the  reducing  flame.  Lanthanium  oxide 
forms  a  white  colorless  glass ;  didymium,  a  dark  amethyst- 
ine glass. 

Iron,  the  peroxide  and  hydrated  peroxide,  become  black 
and  magnetic  before  the  blowpipe,  and  form,  with  borax  or 
salt  of  phosphorus,  in  the  oxidating  flame,  a  dark-red  glass, 
becoming  bright-yellow  when  cold ;  and  in  the  reducing 
flame,  especially  on  adding  tin,  an  olive-green  or  mountain- 
green  glass.  The  peroxide  colors  a  bead  of  borax  contain- 
ing copper  oxide,  bluish-green ;  the  protoxide  produces  red 
spots.  Salts  of  protoxide  of  iron  form  a  green  solution, 
from  which  potassa  or  ammonia  throws  down  the  protoxide 
as  a  hydrate,  which  is  first  white,  then  dirty-green,  and 
finally  yellowish-brown.  Carbonate  of  lime  produces  no 
precipitate.  The  salts  of  the  peroxide,  on  the  other  hand, 
form  yellow  solutions  from  which  the  peroxide  is  thrown 
down  by  potassa  or  ammonia  as  a  flaky-brown  hydrate. 
Carbonate  of  lime  also  causes  a  precipitate. 
•  Chromium  forms,  with  borax  or  salt  of  phosphorus,  a 


128  A  POPULAR  TREATISE  ON  GEMS. 

glass,  fine  emerald-green  when  cold,  though  when  hot  often 
yellowish  or  reddish.  Its  solutions  are  usually  green,  and 
•the  metal  is  thrown  down  by  potassa  as  a  bluish-green  hy -„ 
drate,  again  dissolved  in  excess  of  the  alkali.  The  chrome 
in  many  minerals  is  very  certainly  discovered  by  melting 
the  assay  with  three  times  its  bulk  of  saltpetre,  which,  dis- 
solved in  water,  gives  with  acetate  of  lead  a  yellow  precipitate. 

Vanadium,  melted  on  platinum  wire  with  borax  or  salt 
of  phosphorus,  gives  a  fine  green  glass  in  the  reducing 
flame,  which  becomes  yellow  or  brown  in  the  oxidating 
flame,  distinguishing  it  from  chrome. 

Uranium,  with  salt  of  phosphorus,  forms  in  the  oxidating 
flame  a  clear  yellow ;  in  the  reducing  flame  a  fine  green 
glass.  With  borax  its  reaction  is  similar  to  that  of  iron. 

Molybdenum  forms  in  the  reducing  flame,  with  salt  of 
phosphorus,  a  green  ;  with  borax,  a  brown,  glass.  . 

Tungsten  or  Wolfram  forms,  with  salt  of  phosphorus,  in 
the  oxidating  flume,  a  colorless  or  yellow,  in  the  reducing 
flame,  a  very  beautiful  blue  glass,  which  appears  green 
when  warm.  AYhen  accompanied  by  iron,  the  glass  is  blood- 
red,  not  blue.  Or  melt  the  assay  with  five  times  as  much 
soda  in  a  platinum  spoon,  dissolve  it  in  water,  filter,  and 
decompose  the  result  with  hydrochloric  acid,  which  throws 
down  the  tungstic  acid,  which  is  white  when  cold,  but 
citron-yellow  when  heated. 

Tantalium,  as  tantalic  acid,  is  readily  dissolved  by  salt 
of  phosphorus,  and  in  large  quantity  into  a  colorless  glass, 
which  does  not  become  opaque  in  cooling,  and  does  not 
acquire  a  blue  color  from  solution  of  cobalt.  Or  fuse  the 
assay  with  two  times  as  much  saltpetre,  and  three  times  as 
much  soda,  in  a  platinum  spoon ;  dissolve  this,  filter,  and 
decompose  the  fluid  by  hydrochloric  acid :  the  tantalic  acid 
separates  as  a  white  powder,  which  does  not  become  yellow 
when  heated. 


CLASSIFICATION   OF   MINERALS.  129 

Titanium  in  anatase,  rutile,  brookite,  and  titanite,  is 
shown  by  the  assay  forming,  with  salt  of  phosphorus,  in 
the  oxidating  flame,  a  glass  which  is  and  remains  colorless ; 
in  the  reducing  flame,  a  glass  which  appears  yellow  when 
hot,  and  whilst  cooling  passes  through  red  into  a  beautiful 
vi^fet.  When  iron  is  present,  however,  the  glass  is  blood- 
red,  but  is  changed  to  violet  by  adding  tin.  When  titanate 
of  iron  is  dissolved  in  hydrochloric  acid,  and  the  solution 
boiled  with  a  little  tin,  it  acquires  a  violet  color  from  the 
oxide  of  titanium.  Heated  with  concentrated  sulphuric 
acid,  the  titanate  of  iron  produces  a  blue  color. 


CHAPTER  IV. 

CLASSIFICATION  OF  MINERALS. 

A  MINERAL  species  was  formerly  defined  as  a  natural  in- 
organic body,  possessing  a  definite  chemical  composition 
and  peculiar  external  form.  The  account  given  of  these 
properties  shows  that  the  form  of  a  mineral  species  compre- 
hends not  only  the  primary  or  fundamental  figure,  but 
all  those  that  may  be  derived  from  it  by  the  laws  of  crys- 
tallography. Irregularities  of  form  arising  from  accidental 
causes,  or  that  absence  "of  form  which  results  from  the 
limited  space  in  which  the  mineral  has  been  produced,  do 
not  destroy  the  identity  of  the  speeies.  Even  amorphous 
masses,  when  the  chemical  composition  remains  unaltered, 
are  properly  classed  under  the  same  species,  as  the  perfect 
crystal. 

•The  definite  chemical  composition  of  mineral  species 
must  be  taken  with  equal  latitude.  Pure  substances,  such 
as  they  are  described  in  works  on  chemistry,  are  very  rare 


130  A   POPULAR   TREATISE    ON   GEMS. 

in  the  mineral  kingdom.  In  the  most  transparent  quartz 
crystals,  traces  of  alumina  and  iron  oxide  can  be  detected ; 
the  purest  spinel  contains  a  small  amount  of  silica,  and  the 
most  ^brilliant  diamond,  consumed  by  the  solar  rays,  leaves 
some  ash  behind.  Such  non-essential  mixtures  must  be 
neglected,  or  each  individual  crystal  would  form  a  distiiHt 
mineral  species.  The  isomorphous  elements  introduce  a 
wider  range  of  varieties,  and  render  the  limitation  of  species 
more  difficult. '  Carbonate  of  lime,  for  instance,  becomes 
mixed  with  carbonate  of  magnesia  or  of  iron  in  almost 
innumerable  proportions;  and  the  latter  substances  also 
with  the  former.  Where  these  mixtures  are  small  in  amount, 
variable  in  different  specimens,  and  do  not  greatly  affect 
the  form  or  physical  characters  of  the  predominant  element, 
they  may  safely  be  neglected,  and  the  mineral. reckoned  to 
that  species  with  which  it  most  closely  agrees.  "Where, 
however,  the  mixture  is  greater,  and  the  two  substances 
are  frequently  found  in  definite  chemical  proportions,  these 
compounds  must  be  considered  as  distinct  species,  espe- 
cially should  they  also  show  differences  in  form  and  other 
external  characters. 

Amorphous  minerals  with  definite  composition  must  also 
be  considered  as  true  species.  But  when  they  show  no 
definite  composition,  as  in  many  substances  classed  as  clays 
and  ochres,  they  cannot  be  accounted  true  mineral  species, 
and  properly  ought  not  to  be  included  in  a  treatise  on 
mineralogy.  Some  of  them,  however,  from  their  import- 
ance in  the  arts,  others  from  other  circumstances,  have  re- 
ceived distinct  names  and  a  kind  of  prescriptive  right  to  a 
place  in  mineralogical  works,  from  which  they  can  now 
scarcely  be  banished.  Many  of  them  are  properly  rocks, 
or  indefinite  combinations  of  two  or  more  minerals  $  others 
are  the  mere  products  of  the  decomposition  of  such  bodies. 
Their  number  is  of  course  indefinite,  and  their  introduction 


•   CLASSIFICATION    OF   MINERALS.  131 

tends  much  to  render  mineralogy  more  complex  and  diffi- 
cult, and  to  destroy  its  scientific  character. 

In  collecting  the  species  into  higher  groups,  and  arrang- 
ing them  in  a  system,  several  methods  have  been  pursued. 
Some,  like  Mobs,  have  looke.d  only  at  the  external  charac- 
ters, and  asserted  that  they  alone  were  sufficient  for  all  the 
purposes  of  arranging  and  classifying  minerals.  Others, 
led  by  Berzelius,  foave,  on  the  contrary,  taken  chemistry  as 
the  foundation  of  mineralogy,  and  classed  the  species  by 
their  composition,  without  reference  to  form  or  physical 
characters. 

Neither  system  can  be  exclusively  adopted,  and  a  nat- 
ural classification  of  minerals  should  take  into  account  all 
their  characters,  and  that  in  proportion  to  their  relative 
importance.  Among  these  the  chemical,  composition  un- 
doubtedly holds  a  high  rank,  as  being  that  on  which  the 
other  properties  will  probably  be  ultimately  found  to  de- 
pend. Next  in  order  is  their  crystalline  form,  especially 
as  exhibited  in  cleavage ;  and  then  their  other  characters 
of  gravity,  hardness,  and  tenacity.  But  the  properties  of 
minerals  are  as  yet  far  from  showing  that  subordination 
and  co-relation  which  has  been  observed  in  the  organic 
world,  where  the  external  forms  and  structures  have  a  direct 
reference  to  the  functions  of  the  living  being.  Hence,  even 
when  all  the  characters  are  taken  into  account,  there  is  not 
that  facility  in  classifying  the  mineral  that  is  presented  by 
the  other  kingdoms  of  nature.  Many,  or  rather  most,  of 
the  species  stand  so  isolated  that  it  is  scarcely  possible  tp 
find  any  general'  principle  on  which  to  collect  them  into 
large  groups,  especially  such  groups  as,  like  the  natural 
families  of  plants  and  animals,  present  important  features 
of  general  resemblance,  and  admit  of  being  described  by 
common  characteristics.  Certain  groups  of  species  are 
indeed  united  by  such  evident  characters,  that  they  are 


132  A   POPULAR   TREATISE    ON   GEMS.    * 

found  together  in  almost  every  method  ;  but  other  species 
are  not  thus  united,  and  the  general  order  of  arrangement 
is  very  uncertain.  Hence,  though  some  classifications  of 
very  considerable  merit  have  been  proposed,  no  natural 
system  of  minerals  commanding  general  assent  has  yet 
appeared.  . 

The  arrangement  followed  in  this  treatise  is  chiefly 
founded  on  that  proposed  by  Professor  Weuss  of  Berlin. 
We  have,  however,  made  considerable  changes,  which  the 
progress  of  the  science  and  the  more  accurate  knowledge 
of  many  species  require.  This  classification  appears  to  us 
to  come  nearer  than,  any  other  we  have  seen  to  a  natural 
system,  which  in  arranging  and  combining  objects  takes 
account  of  all  their  characters,  and  assigns  them  their  place, 
from  a  due  consideration  of  their  whole  nature,  and  is  thus 
distinguished  from  artificial  systems,  which  classify  objects 
with  reference  only  to  one  character. 

Besides  species,  two  higher  grades  in  classification  seem 
sufficient  at  once  to  exhibit  the  natural  relations,  and  to 
facilitate  .an  easy  and  complete  review  of  the  species  com- 
posing the  mineral  kingdom.  These  are  families  and  orders. 
In  forming  the  families,  those  minerals  are  first  selected 
which  occupy  the  more  important  place  in  the  composition 
of  rocks,  and  consequently  in  the  crust  of  the  globe.  Thus 
quartz,  felspar,  mica,  hornblende,  garnet,  among  siliceous 
minerals;  calc-spar,  gypsum,  rock-salt,  less  so  fluor  spar 
and  heavy  spar,  among% those  of  saline  composition,  stand 
out  prominently  as  the  natural  centres  or  representatives  of 
so  many  distinct  families.  To  these  certain  metallic  miner- 
als, as  iron  pyrites,  lead-glance  or  galena,  blende,  magnetic 
iron  ore,  the  sparry  iron  ore,  and  a  few  more,  are  readily 
associated  as  important  families.  But  the  minerals  thus 
geologically  distinguished  are  not  sufficient  to  divide  the 
whole  mineral  kingdom  into  convenient  sections,  and  addi- 


CLASSIFICATION    OP    MINERALS.  133 

tional  groups  must  be  selected  from  the  peculiarity  of  their 
natural-historical  or  chemical  properties.  Thus  the  zeo- 
lites are  easily  seen  to  form  such  a  natural  group.  The 
precious  stones  or  gems  also,  notwithstanding  their  diverse 
chemical  composition,  must  ever  appear  a  highly  natural 
family,  when  regarded  as  individual  objects.  Their  great 
hardness,  tenacity,  high  specific  gravity  without  the  me- 
.tallic  aspect,  their  brilliant  lustre,  transparent  purity,  and 
vivid  colors,— all  mark  them  out  as  a  peculiar  group.  Only 
the  diamond,  which  might  naturally  seem  to  take  the  chief 
place  in  this  class,  differs  so  much,  not  only  in  elementary 
composition,  but  in  physical  properties,  that  it  must  be 
assigned  to  a  different  place. 

Round  these  .species  thus  selected,  the  other  Jess  import- 
ant minerals  are  arranged  in  groups  or  families.  It  is  evi- 
dent? that  no  precise  definition  of  these  families  can  be 
given,  as  the  connection  is  one  of  resemblance  in  many 
points,  not  of  identity  in  any  single  character.  In  other 
words,  it  is  a  classification  rather  according  to  types  than 
from  definitions,  as  every  true  natural  classification  must 
be.  The  same  cause,  however,  leaves  the  extent  of  the 
families  somewhat  undefined,  and  also  permits  considerable 
license  in  the  arrangement  of  species.  But  both  circum- 
stances are  rather  of  advantage  in  the  present  state  of  the 
science,  as  allowing  more  freedom  in  the  grouping  of  spe- 
cies than,  could  be  obtained  in  a  more  rigid  system  of  clas- 
sification. 

In  collecting  the  families  into  orders,  the  guidance  ot 
chemistry  is  followed  rather  than  of  natural  history,  thougli 
the  latter  is  also  takenjnto  consideration.  Chemical  names 
are  assigned  to  the  orders,  but  still  regarded  as  names  de- 
rived from  the  prevailing  chemical  characters,  and  not  as 
definitions.  Hence  it  must  not  be  consider^!  an  error 
should  two  or  three  mineral  species  be  found  in  an  order 


134  A  POPULAR  TREATISE  ON  GEMS. 

with  whose  name,  viewed  as  a  definition,  they  may  not 
agree. 

Guided  by  these  and  similar  considerations,  minerals 
may  be  divided  into  the  following  orders  and  families : 

ORDER  I. — THE  OXIDIZED  STONES. 

Families.— -1.  Quartz.  8.  Serpentine. 

2.  Felspar.  9.  Hornblende. 

3.  Scapolite.  10.  Clays. 

4.  Haloid  stones.  11.  'Garnet. 

5.  Leucite.  12.  Cyanite. 

6.  Zeolite.  13.  Gems. 

7.  Mica.  14.  Metallic  stones.' 

ORDER  II.— SALINE  STONES. 
families. — 1.  Calc  spar.  4.  Gypsum. 

2.  Fluor  spar.  5.  Kock  salt.  * 

3.  Heavy  spar. 

ORDER  III. — SALINE  ORES. 

Families.— -1.  Sparry  iron  ores.  8.  Copper  salts. 

2.  Iron  salts.  4.  Lead  salts. 

ORDER  IV. — OXIDIZED  ORES. 
Families.— I.  Iron  ores.  4.  Red  copper  ores. 

2.  Tinstone.  5:  White  antimony  ores. 

3.  Manganese  ores. 

ORDER  V. — NATIVE  METALS. 
Form  only  one  family. 

ORDER  VI. — SULPHURETTED  METALS. 
Families.— I.  Iron  pyrites.  4.  Gray  copper  ore. 

2.  Galena.  5.  Blende. 

3.  Gray  antimony  ore.          6.  Ruby-blende. 

•  • 

ORDER  VII. — THE  INFLAMMABLES. 

Families.— I.  Sulphur.  4.  Mineral  resins. 

Diamond.  5.  Combustible  salts. 

Coal. 


PART  II. 
THE    GEMS. 

• 
+  *  »    

PRECIOUS   STONES   OK   GEMS. 

PRECIOUS  stones  or  gems  are  such  minerals  as,  either  from 
their  beauty  or  other  valuable  properties,  have  become  the 
subject  of  the  arts  or  trade,  and  are  used  as  ornaments,  or 
employed  by  jewellers.  In  order  to  appreciate  more  fully 
such  minerals  as  may  possess  superior  virtue,  it  is  our  pres- 
ent object  to  consider  them  in  reference  to  their  scientific 
and  practical  value. 

DIVISION   OF   GEMS. 

Gems  are  generally  classed  as  follows:  1st,  real  gems,  or 
jewels ;  and  2d,  semi-gems,  or  also  precious  stones.  The  first 
comprise  such  minerals  as  combine,  within  a  small  space, 
either  vivid  or  soft  and  agreeable  colors,  with  a  high  de- 
gree of  lustre,  usually  termed  fire,  as  well  as  hardnes's; 
the  second  possess  these  characters  in^a  less  degree,  and 
occur  often  semi-transparent  or  translucent,  and  in  larger 
formless  masses.  It  is,  however,  impossible  to  draw  a 
Gtrict  line  between  them,  as  the  conventional  value  put  upon 
the  one  or  the  other  also  affects  their  character ;  for  very 
often  some,  which  are  generally  considered  as  belonging 
to  the  second  class,  may  be  valued,  for  their  peculiar  prop- 
erties, much  higher  than  some  of  the  first  class. 


136  A   POPULAR   TREATISE    ON    GEMS. 

Those  species  of  minerals  which  are  generally  considered 
real  gems  are — 

Diamond,  Garnet, 

Sapphire,  Tourmaline, 

Chiysoberyl,  Rubellite, 

Spinelle,  Essonite, 

Emerald,  Cor.dierite, 

Beryl,  .  lolite, 

Topaz,  Quartz, 

Zircon,  Chrysolite. 

The  rest  are  considered  as  semi-precious  stones. 


COLOR,    GRAVITY,    AND   HARDNESS    OF   GEMS. 

The  precious  stones  possess  the  colors  in  their  highest 
perfection,  and  their  principal  and  intrinsic  value  depends 
mostly  upon  this  property ;  and  as  most  gems  occur  in  va- 
rious colors,  the  following  table  will  exhibit  them,  along 
with  their  specific  gravity  and  hardness : 

LIMPID  "GEMS. 

SPECIFIC  GRAVITY.  HAKDNESS. 

Zircon 4-41  to  470  7'5 

Sapphire 3-9  4-20  7- 

Diamond 3-5  3'6  10' 

Topaz  (Pebble) 3-49  3-56  8- 

Eock  Crystal  (False  Diamonds,  Lake  George, 

•  Trenton  Falls) 2'69  7* 

Beryl,  Aquamarine , 2-67  2'68  7'5 

BED    GEMS. 

Zircon,  Hyacinth 4-41  4-70  7'5 

Garnet  (Oriental  Garnet) 4'0  4-2  6'5 

Sapphire,  Ruby ..  4>0  4'2  9' 

Garnet,  Bohemian  Garnet.    Pyrop 3'7  3'8  6'5 

Spinelle,  Ruby  Spinelle,  Ruby  Balais 3'49  3*7  8- 

Diamond 3-5  3*6  10- 

Essonite 3'5  3-6  7' 

Topaz.   "Brazilian  Topaz  (often  burnt) 3'52  8'56  8- 


GRAVITY  AXD  HARDNESS  OF  GEMS.  137 

SPECIFIC   GRAVITY.  HABDUKSS. 

Tourmaline,  Siberite,  Eubellite 3*0    to    3-30  6*5 

Rose  Quartz.     Bohemian  Ruby 2'50  2*63  7' 

Carnelian 2'5  2'6  ?• 

• 

YELLOW    GEMS. 

Zircon 4-41  4'50  7 '5  . 

Sapphire.     Oriental  Topaz ; '. .  4-0  8- 

Chrysoberyl 3'65  3'80  8'5 

Topaz.    Brazilian,  Saxonian,  and  Syrian  Topaz  3'50  3'56  8' 

Diamond '. . . .  3-5  3-6  10* 

Beryl ; 2'67  2'7l  1'S 

Rock  Crystal,  Citron 2'60  2'69  7- 

Fire-opal 1-90  2-12  5-5 

GREEN   GEMS. 

Zircon 4-41  4'50 

Sapphire,  Oriental  Chrysolite,  and  Emerald ..   3'9  4'00  V 

Malachite 3>6T  3-5 

Chrysoberyl 3'59  3'75  8'5 

Spinelle , 3-58  3'64  8' 

Diamond 3-5  3'6  10' 

Topaz.     Aquamarine 3-49  3-56  s* 

Chrysolite 3'33  3'44  6'5 

Idocrase 3'08  3'40  6'5 

Tourmaline  (Brazilian  and  Maine) 3'00  3-30  6-5 

Emerald.. * 2'67  2'73  7'5 

Berj'l 2-67  271  7'5 

Prase... 2-66  2'6S  f- 

HeHotrope 2'61  2-63  7" 

Chrysoprase 2'5S  2-60  7- 

Felspar,  Amazon  Stone 2'50  2'60  6' 

BLUE   OEMS. 

Sapphire 3'90  4'00  8' 

Disthene  (Kyanite) '. ,  .  3'50  S'67  5' 

Spinelle 3'58  3'64  8' 

Diamond 3'5  3'6  10- 

Topaz.  •  Brazilian  Topaz 3-49  3'5ft  S- 

Tourmaline,  Indigolite : 3'00  3'30  6'5* 

Turquoise 2*86  3*00  6- 

Beryl,  Aquamarine .*  2-67  2*71  7'5 

Dichroite  (loUte) 2-58  2-60  7* 


138  A   POPULAR   TREATISE    ON   GEMS. 

SPECIFIC  GRAVITY.  HARDNESS, 

Hauyne 2-47  5' 

Lazulite 2-30  5- 

*  VIOLET   GEMS. 

Garnet 4'0     to  4-2  6'5 

.  Sapphire,  Oriental  Amethyst 3!9  4'0  9- 

Spinelle '. 3'58  3'64  8* 

Axinite 3'27  6'5 

Tourmaline 3'00  3'30  6'5 

Amethyst : 2-65  2'7S  7' 

BROWN   GEMS. 

Zircon 4'41  4'50  7'5 

Garnet ' 4-00  4'20  6'5 

Essonite 3-53  3'60  7' 

Diamond 3'50  3-60  10' 

Toifrmaline 3'00  3-30  6*5 

Smoky  Quartz .2-69  2*70  7' 

BLACK   GEMS. 

Diamond 3-50  3'60  10* 

Tourmaline 3'00  3'30  6' 

Eock  Crystal,  Morion 2'69  2'7l  7' 

Obsidian 2-34  2'39  6"-o 

Pitch  Coal •. 1-29  1-35  2- 

CannelCoal : 1*23  1'27  2' 

GEMS   DISTINGUISHED   FOK  THEIR  VARIOUS   SHADINGS   OF   COLOR 
AND  LIGHT. 

Garnet 4-00  4'20  6-5 

Sapphire,  Star  Sapphire 3'90  4'00  9- 

Chrysoberyl 3*70  3'SO  8'5     ' 

Hypersthene 3'38  6- 

'    Labrador  Spar 2-71  2'75  6- 

Dichroite 2'58  2'60  7' 

Cat's-eye .* 2'56  2'73  7' 

Adularia 2-50  2'60  6' 

Felspar 2'50  2'60  6- 

•Precious  Opal 2-00  2-10  5'5 

Hydrophane 1'90  2'00  5- 

• 

A  number  of  precious  stones  do  not  possess  a  local  color, 


COMPOSITION   OF    GEMS.  139 

but  merely  a  tinge  or  a  shade  of  color ;  and  these  we  dis- 
tinguish by  the  following  degrees  of  dark,  high,  light,  and 
pale  colored,  or  tinged.  Another  distinction  may  be  de- 
tected in  precious  stones  as  possessing  either  one  or  more 
colors,  or  a  variegated  color ;  or  as  being  spotted,  painted, 
stained  with  the  different  colors.  These  latter  characters 
are,  however,  more  proper  to  the  semi  or  common  precious 
stones,  than  to  gems. 

CHEMICAL   CHARACTERS. 

Although  mineralogy  could  nqt  exist,  as  a  science,  with- 
out the  aid  of  chemistry,  and  whole  systems  or  classifica- 
tions have  been  established,  as  well  as  the  constituent  parts 
of  minerals  determined,  by  the  knowledge  of  Chemical  char- 
acters, still  it  is  difficult  to  resort  to  chemical  means  for  dis- 
tinguishing the  gems  or  precious  stones,  as  they  would  be 
destroyed  by  such  an  examination,  and  we  can,  for  that 
purpose,  only  employ  splinters  or  fragments.  The  most 
simple  mode  of  proceeding  is  to  test — 

1st,  Their  greater  or  less  fusibility,  with  or  without  a  flux ; 

2d,  Their  behavior  before  the  blowpipe,  an  instrument 
highly  convenient,  and,  indeed,  indispensable  to  the  miner- 
alogist ;  and, 

3d,  The  action  of  the  acids  upon  them. 

All  of  these  means,  however,  have  not  an  effect  upon  all 
gems,  as  many  of  them,  for  instance,  are  either  infusible,  or 
fusible  with  the  greatest  difficulty  by  the  addition  of  a  flux. 

COMPOSITION   OF   GEMS. 

The  attention  "of  writers,  as  far  back  as  1502,  had  been 
directed  to  the  establishment  of  some  hypothesis  as  to  the 
composition  .and  origin  of  the  gems,  and  many  fabulous* 
views  were  entertained  in  respect  to  their  formation. 

There  was  also  connected  with  some  hypotheses  a  species 


140  A   POPULAR   TREATISE   ON   GEMS. 

of  medical  superstition  as  to  their  effect.  Boyle  (1672) 
thought  that  all  gems  were  originally  formed  from  clear 
limpid  water,  and  that  they  received  their  color  and  other 
properties  from  their  metallic  spirit.  Others  considered  a 
peculiar  earth,  called  the  noble  or  precious  earth,  as  the 
principal  ingredient  of  the  precious  stones.  Bruckman 
(1778)  recognized  quartz  as  the  principal  of  the  gems. 
Bergman  thought  that  gems  were  all  composed  of  the  same 
ingredients,  such  as  alumina,  silex,  and  lime,  and  that  the 
different  proportions  produced  the  different  species ;  and 
the  older  mineralogists  determined  the  character  of  the 
gems  by  their  hardness,  lustre,  structure,  and  resistance  to 
acids.  But  modern  chemistry  has  ascertained  the  compo- 
nent parts,  and  other  characters  of  gems,  with  more  cer- 
tainty, and  it  is  satisfactorily  proved  that  the  principles 
they  contain  are  the  earths,  such  as  silica,  alumina,  and 
lime ;  that  some  contain  a  peculiar  earth  (such  is  the  case 
with  the  zircon,  emerald,  and  chrysoberyl),  and  that  the 
diamond,  at  the  head  of  gems,  consists  of  pure  carbon,  <fcc. 

THE   ARTIFICIAL   PRODUCTION    OF   GEMS   AND   MINERALS. 

Professor  Mitscherlich  has  produced,  artificially,  crystals 
of  minerals  by  fusion  at  a  high  temperature  of  the  scoria 
of  furnaces  containing  silicates,  with  the  addition  of  such 
oxides  as  form  a  component  part  of  the  respective  minerals, 
exposed  to  a  high  heat.  So  successful  was  the  result,  that  he 
produced  more  than  forty  species  of  the  various  crystalline 
minerals  artificially,  and  corresponding  with  the  natural 
productions,  such  as  peridote,  pyroxene,  mica,  felspar,  pro- 
toxide of  copper,  iron  pyrites,  and  others.  Berthier  devoted 
likewise  some  time  in  reproducing  several  minerals  by  fusion 
at  a  high  temperature,  and  he  has  obtained  crystals  of  peri- 
dote  and  pyroxene  with  iron  and  manganese  bases,  which 
were  for  a  long  time  called  silicate  of  manganese. 


ARTIFICIAL    PRODUCTION    OF    GEMS/  141 

Mr.  Gaudin  has,  by  means  of  the  compound  blowpipe, 
been  able  to  fuse  alumina  and  quartz,  and  from  potassa 
and  ammoniacal  alum  he  has  produced  well-formed  co- 
rundum crystals,  as  also  crystals  of  ruby,  of  rhombohe- 
dral  form  and  triple  cleavage,  and  which,  according  to 
Malagutti,  consisted  of  ninety-seven  alumine  and  two  silicate 
of  lime,  the  exact  composition  of  ruby.  By  this  process 
the  potassa  originally  employed  was  volatilized  in  the  high 
temperature;  this  was  done  in  1837.  Becquerel  employed 
electricity  for  this  purpose  in  its  most  attenuated  condition, 
and  with  two  or  three  bodies,  one  of  which  in  its  dry  and 
the  other  in  liquid  state,  and  required  from  one  to  two 
years  to  effect  its  object,  as  the  case  was  with  a  dodecahe- 
dral  pentagonal  crystal  of  iron  pyrites ;  he  obtained  sulphu- 
rets  of  copper  and  tin,  which  could  not  be  distinguished 
from  the  native  crystals.  He  has  even  obtained  crystals  of 
oxide  of  zinc,  which-  were  octahedral,  transparent,  refract- 
ing strongly  the  light,  and  hard  enough  to  scratch  glass, 
and  altogether  unknown  in  the  mineral  kingdom.  His 
process  was,  on  a  silicate  of  potassa  solution  to  let  act- 
slowly  a  voltaic  current  from  a  sheet  of  zinc,  around  which 
a  copper  wire  was  wound.  The  density  of  the  liquid  was 
22°  areometer;  water  was  thereby  decomposed  with  dis- 
engagement of  hydrogen  gas  and  formation  of  oxide  of 
zinc,  which  was  dissolved  again,  and  after  a  fortnight,  very 
fine  brilliant  crystals  were  visible  on  the  zinc  plate,  which, 
after  a  lapse  of  two  years,  were  the  size  of  a  millimeter. 

Mr.  Ebelman  conceived  the  idea  of  obtaining  artificial^ 
crystals  from  infusible  silicates  and  aluminates,  by  replac- 
ing the  water  contained  in  many  metallic  oxides  in  higli 
temperatures  with  boracic  acid,  borate  of  soda,  phosphorus, 
and  alkaline  phosphates,  and  its  final  evaporation  in  high 
temperatures.  He  prepared  certain  oxides,  calculating 
the  proportions,  such  as  alumina  and  silica,  and  exposed 


142        'A  POPULAR  TREATISE  ON  GEMS. 

them  in  a  platina  capsule,  at  a  high  temperature,  in  his 
porcelain  furnace  of  the  Sevres  manufactory,  of  which  he 
was  the  director,  and  with  the  mixture  of  boracic  acid  kept 
the  mass  in  a  fusion,  and  the  corundum  and  crystallized 
silex  were  the  results.  He  used  boracic  acid  for  this  purpose, 
•  as  he  found  it  more  convenient  than  the  other,  dissolvents. 

Mr.  Ebelman  has  fused  together,  in  order  to  obtain  the 
spinelle  (which  is  composed  of.  72  parts  of  alumina  and  28 
parts  magnesia), 

Alumina,      -  -  G  grammes. 

Magnesia,     -  -.  3       " 

Fused  boracic  acid,       -  6       "  . 

Green  oxide  of  chrome,  O'1-O  to  0*15  grammes. 
The  latter  was  added  for  the  purpose  of  rendering  the  mass 
of  a  rose  color.  This  mixture,  put  into  an  uncovered  pla- 
tina capsule,  was  exposed  to  the  heat  of  the  porcelain  fur 
nace ;  after  the  baking  was  finished,  the  melted  mass  formed 
a  rose-colored  layer  on  the  bottom  of  the  capsule,  and  in 
the  mass  octahedral  crystals  of  spinelle,  quite  identical  with 
•the  natural  crystals  of  the  ruby  spinelle,  were  taken  out, 
which  were  exceedingly  Brilliant.  The  author  received  in 
1851,  while  on  a  visit  to  Paris,  from  Mr.  Ebelman,  about 
thirty  of  those  crystals,  weighing  about  one  grain,  and 
which  he  submitted,  on  his  return  to  the  United  States,  to 
numerous  chemical  and  mineralogical  tests,  both  as  to 
hardness,  specific  gravity,  and  lustre,  and  was  extremely 
gratified  as  to  its  results. 

Mr.  Ebelman  manufactured  the  blue  spinelle,  by  substi- 
tuting the  same  quantity  of  oxide  of  cobalt  for  the  oxide  of 
chrome;  also  by  substituting  the  oxide  of  zinc  for  .the 
magnesia,  he  obtained  the  garnet,  which  he  prepared  by 
Alumina,  -  6  grammes. 

Oxide  of  zinc,         -  5   *    " 
Fused  boracic  acid,  6        " 


ARTIFICIAL    PRODUCTION    OF    GEMS.  143 

The  mass  was  brought  slowly  to  a  white-heat  temperature, 
and  kept  from  twenty-four  to  thirty  hours  in  that  condition. 
The  boracic  acid  begins  to  evaporate  during  the  last  five 
hours. 

The  emerald  was  obtained  artificially  by  a  mixture  of 

Silex,      -  -4      grammes. 

Alumina,  -  T60       " 

Glucia,    -  -  1-40       " 

Fused  boracic  acid;  4*06       " 

Oxide  chrome,        -  O'lO       " 

Mr.  Daubree  has  produced  artificially  the  oxide  of  tin, 
by  passing  through  a  heated  porcelain  tube  two  currents 
of  the  vapors  of  the  perchloride  of  tin  and  water,  by  which 
a  double  decomposition  was  effected,  so  that  in  the  interior 
of  the  porcelain  tube  small  crystals  of  oxide  of  tin  were  de- 
posited, arid  hydrochloric  acid  gas  passed  off  in  the  form  of 
vapor.  The  crystals  of  tin- were  deposited  at  the  orifice  of 
the  porcelain  tube,  where  the  temperature  was  scarcely 
300°,  while  no  crystals  were  deposited  in  the  hottest  part ; 
the  crystals  of  tin  scratched  glass  easily,  were  infusible, 
and  were,  not  affected  by  acids,  and  had  a  specific  gravity 
of  6-72. 

The  latest  discoveries  of  Mr.  Daubree  have  .brought  to 
•  light  many  important  facts  in  regard  to  the  formation  of 
rocks  which  contain  crystalline  substances,  differing  widely 
in  their  fusibility.  By  the  action  of  chloride  of  silicium  at 
red  heat,  and  vapor  on  many  bases  which  enter  into  various 
rocks  he  obtains  in  exchange,  by  decomposition,  chlorine 
bases  and  free  silica  (silicic  acid),  which  appears  as  quartz 
in  crystals  ;  if  he  desires  an  action  of  the  chloride  of  sili- 
cium on  chalk,  magnesia,  alumina,  or  glucia,  he  obtains 
crystals  of  quartz,  wallastonite,  peridote,  and  -disthene ;  for 
the  purpose  of  obtaining  double  silicates,  he  not  only  adds 
the  bases  for  silicifying  in  proper  proportions,  but  also  in 


144  A    POPULAll    TKEATISE    ON    GEMS. 

excess  sufficient  oxygen  for  forming  silicic  acid.  A  mixture 
of  chalk  or  magnesia,  for  instance,  to  the  chloride  of  sili- 
cium,  produced  crystals  of  diopside,  perfectly  colorless, 
with  a  characteristic  slope  of  this  mineral.  He  also  ob- 
tained crystallized  felspar  by  the  mixture  of  1  equivalent 
of  alkali  (potassa  and  soda),  1  equivalent  of  alumina,  with 
6  equivalents  of  lime  under  the  influence  of  chloride  of  si- 
licium.  Similar  mixtures  have  produced  crystals  of  garnet, 
idocrase,  phenakite,  emerald,  euclase,  zircon,  and  wilhelm-" 
ite.  He  also  produced  tourmaline  in  regular  hexagonal 
prisms,  which  were  grouped  upon  quartz  crystals  just  as 
they  are  often  observed  in  crystalline  rocks  of  shorl.  By 
the  same  method,  but  replacing  the  chloride  of  aluminum 
for  action  upon  the  bases,  he  obtained  corundum  crystals, 
spinelle  crystals,  and  garnet  crystals ;  by  the  contact  of 
perchloride  of  iron  with  chloride  of  zinc  he  obtained  fine 
crystals  of  franklinite ;  crystals  •  of  magnesia  or  periclase, 
like  those  from  Mount  Somma,  were  produced  by  the 
action  of  lime  on  chloride  of  magnesium,  but  remarkable 
enough,  their  production  is  just  the  counterpart  of  the  ori- 
gin of  the  native  mineral,  where  constantly  chlorine  vapors 
are  disengaged,  and  where  it  detaches  itself  from  the  dolo- 
mite geodes. 

Mr.  Durocher  obtained,  by  the  action  of  sulphuretted 
hydrogen  gas  upon  the  chlorides  of  iron  and  zinc,  crystals 
of  magnetic  pyrites  and  blende ;  he  also  obtained,  by  the 
action  of  different  vapors,  sulphurets  of  antimony  and 
arsenic,  and  the  gray  antimonial  copper. 

Mr.  Senarmont  obtains  quartz  crystals  in  perfect  hexag- 
onal prisms,  with  all  the  other  specific  characters,  from  the 
gelatinized  silica,  under  a  high  temperature  and  the  high 
pressure  of  thirty  atmospheres. 

The  artificial  production  of  the  diamond  has  been  latterly- 
effected  by  the  ingenious  contrivance  of  Despretz,  which 


GEOLOGICAL   CHARACTERS.  145 

consists  in  passing  an  electric  current  "into  an  exhausted 
bottle,  in  the  lower  part  of  which  is  placed  a  small  cylinder 
of  charcoal,  and  from  the  upper  part  "are  suspended  pla 
tina  wires  or  platiua  foils;  the  sparks  thereby  obtained 
from  the  combustion  of  the  charcoal  are  of  a  reddish-violet 
color ;  after  the  lapse-of  one  month,  during  which  the  com- 
bustion continues,  a  little  black  layer  of  charcoal  is  depos 
ited  upon  the  platina ;  under  the  microscope  they  appear 
like  very  small  octahedrons,  quife  analogous  to  the  dia- 
mond ;  some  were  free  from  color,  and  very  brilliant. 

GEOLOGICAL   CHARACTERS. 

The  origin,  locality,  and  geological  characters  of  gems 
are  various ;  it  was  formerly  supposed  that  the  trap  forma- 
tion was  their  matrix ;  but  it  is  ascertained  that  we  find 
them  distributed  in  rocks  of  different  ages  and  kinds,  either 
as  accidental  mixtures — such  as  garnet  in  gneiss  and  mica- 
ceous schiste — or  in  drusy  cavities,  such  as  the  emerald, 
which  occurs  in  druses  of  argillaceous  slate  and  micaceous 
schiste ;  and  many  precious  stones  are  found-  in  gangues. 
Many  gems  are  found  at  a  distance  from  their  original  bed, 
on  secondary  or  diluvial  strata,  or  &i  the  beds  of  rivers, 
mixed  with  their  sand.  Thus,  zircon  is  found  in  Ceylon  in 
regular  beds ;  and  likewise  we  find  in  Ceylon,  after  much 
rain,  the  topaz,  zircon,  and  other  gems.  This  happens 
more  frequently  in  the  beds  of  the  rivers,  and  then  the 
gems  appear  often  in  the  shape  of  pebbles,  showing  that 
those  hard  stones,  carried  away  from  their  original  beds, 
have  been  rolled  and  rounded  by  the  streams  and  rivers, 
although  they  retain  sometimes  their  crystalline  structure, 
on  account  of  their  hardness. 

The  discovery  of  diamonds  in  Russia,  far  from  the  tropi- 
cal region,  has  excited  "much  interest  among  geologists. 

7 


146  A  POPULAR  TREATISE  ON  GEMS. 

In  the  detritus  on  the  banks  of  the  Adolfskoi,  no  fewer 
than  forty  diamonds  have  been  found  in  the  gold  alluvium, 
only  twenty  feet  above  the  stratum  in  which  the  remains 
of  mammoths  and  rhinoceroses  are  found.  Hence  Hum- 
boldt  has  concluded  that  the  formation  of  gold-veins,  and 
consequently  of  diamonds,  is  comparatively  of  recent  date, 
and  scarcely  anterior  to  the  destruction  of  the  mammoths. 
Sir  Roderick  Murchison  and  M.  Yerneuil  have  been  led  to 
the  same  result  by  different  arguments. 

GEOGRAPHICAL   DISTRIBUTION. 

The  locality  of  gems  bears  some  highly  interesting 
characters,  inasmuch  as  we  may  sometimes  judge,  from 
.  their  appearance,  the  climate  of  their  locality ;  and  it 
seems  as  if  the  countries  of»the  torrid  zone  had  been  par- 
ticularly favored  by  nature  in  producing  the  most  precious 
gems,  or  that  those  hot-beds  were  more  propitious  to  the 
formation  of  the  blossoms  of  the  inorganic  world.  Com- 
paring, for  instance,  spinelles  and  zircons,  from  Siberia, 
with  those  of  Ceylon  and  Peru,  we  find  the  first  to  be  dark 
and  of  an  impure  color,  as  if  emblematic  of  a  cold,  un- 
friendly, northern  climate  ;  whereas  the  latter  glitter  with 
full  brilliancy,  and  possess  all  those  properties  and  beauties 
for  which  gems  are  so  highly  esteemed.  Often,  too,  we 
find  the  gems  collected  in  particular  countries,  or  isolated 
spots  of  our  globe,  such  as  the  most  precious  gems  from 
the  East  Indies  and  Brazil,  where,  singular  enough,  they 
occur  with  the  precious  metals ;  as,  for  instance,  the  dia- 
mond in  company  with  gold  and  platina  in  Brazil.  Some 
of  the  gems  have  likewise  been  hitherto  discovered  in  a 
single  spot  on  one  continent  only,  and  are  then  exhausted*; 
such  as  the  rubellite,  in  Maine,  United  States ;  the  iolite  in ' 
Connecticut,  United  States,  and  the  lazulite  in  Persia. 


NOMENCLATIVE   OF   GEMS.  147 


PRACTICAL   DIVISION   AND    NOMENCLATURE    OF    GEMS.  - 

Artists  have  not  profited,  in  their  arrangement  and  no- 
menclature of  gems,  by  the  advanced  state  of  mineralogy, 
as  a  science ;  and  although  they  have  been  newly  classified 
by  mineralogists  according  to  their  scientific  characters, 
the  practical  artist  arranges  them  according  to  those  prop- 
erties that  principally  attract  the  eye :  such  as  color,  trans- 
parency, and  lustre.  Gems  have,  in  consequence,  received 
their  names  from  their  color :  as  ruby,  from  its  red  color ; 
sardonyx,  yellow  onyx.  Gems  of  different  species,  but  of 
the  same  color,  are  often  named  from  their  color.  For 
instance,  the  corundum,  the  spinelle,  or  the  topaz,  if  of  a  red 
color,  is  called  ruby ;  if  blue,  sapphire ;  if  green,  emerald ; 
if  yellow,  topaz,  and  if  violet,  amethyst :  and  thus  gems  of 
the  same  color,  but  of  different  composition,  are  arranged 
under  the  same  head.  The  artist  confounds  under  the 
name  of  Brazilian  ruby,  either  a  light  rose-red  spinelle, 
or  a  topaz  approaching  to  the  red  color.  The  name  of  a 
country  or  locality,  is  often  sufficient  to  give  a  name  to  gems 
of  the  same  color,  but  of  different  shadings,  and  of  more 
or  less  vivid  lustre.  Thus,  by  Oriental  chrysolite  is  meant 
a  yellowish -green  sapphire,  and  by  Saxonian  chrysolite,  a 
pale  wine-yellow  topaz.  Many  gems  have  always  been 
known  under  the  name  of  Oriental  gems,  partly  because 
they  were  first  obtained  in  the  East,  and  partly  because 
they  stood,  from  their  excellent  properties,  in  higher  esti- 
mation than  those  from  an^  other  country.  Those  from 
the  East  were  likewise  callecf  "  Oriental,"  in  opposition  tQ 
others  less  valuable,  which  were  called  "  occidental"  gems. 
Subsequently,  all  gems  of  superior  qualities  were  called 
Oriental  gems,  even  when  their  locality  was  not  in  the 
East.  Thus,  for  instance,  that  precious  opal,  so  well  dis- 
tinguished for  its  beautiful  play  of  colors,  is  called  the  On- 


148  A   PQPUIAR   TREATISE   ON   GEMS. 

ental  opal,  although  it  is  never  found  there ;  likewise,  the 
purest  and  most  valuable  emerald,  which  in  great  perfection 
only  occurs  in  Peru,  is  known  as  the  Oriental  emerald. 


HISTORY    OF    GEMS. 

Those  precious  stones,  which  are  now  called  gems,  were 
known  in  ancient  times  but  very  little,  if  at  all.  The  first 
notice  given  of  them  is  in  the  Bible,  where  it  is  stated  that 
the  high  priest  wore  one  stone  on  his  gold  scarf,  and  twelve 
gems  set  in  gold  plate,  called  the  Urim  and  Thummim, 
each  of  which  represented  a  tribe.  It  appears  that  the 
Hebrews  borrowed  the  names  of  their  gems  from  the 
Egyptians,  and  few  of  the  gems — with  the  exception  of 
the  sapphire — named  in  the  holy  Scriptures  correspond  in 
any  respect  with  those  at  present  known  in  our  mineralogical 
books.  The  Greeks  appear  to  have  been  but  little  ac- 
quainted with  gems,  as  they  did  not  use  them  as  ornaments 
in  the  Trojan  wars;  and  Homer,  when  speaking  of  the 
treasures  of  those  tunes,  does  not  make  any  mention  of 
gems.  Theophrastus  and  Pliny  have  described  some  gems 
of  their  time  very  imperfectly  and  confusedly ;  and  their 
descriptions  are  so  replete  with  vain  fancies,  that  it  is  diffi- 
cult to  identify  any  from  their  descriptions.  They  attributed 
most  wonderful  powers  to  gems ;  gave  fabulous  descriptions, 
and  the  most  singular  and  perverted  views  in  regard  to 
their  origin ;  and  it  was  said  that  they  had  great  influence 
upon  health  and  beauty,  riches,  honor,  and  good  fortune. 
They  were  called,  when  worn,*amulets.  They  were  brought 
into  connection  with  the  planets,  the  twelve  constellations, 
and  the  seasons  of  the  year ;  and  a  certain  gem  was  worn 
each  month,  which  was  said  to  have  during  the  term,  its  pe- 
culiar influence  and  healing  virtues.  Such  superstitious 
notions  have  been  transmitted  to  our  times.  The  gems  cor- 


HISTORY   O?   GEMS.  14p 

responding  to  the  different  months,  and  also  to  the  twelve 
Jewish  tribes,  are  the  following : 

January Hyacinth "Dan. 

February Amethyst Gad. 

March Jasper Benjamin. 

April Sapphire Issaehar. 

May Agate Naphtali. 

June Emerald Levi. 

July Onyx Zebulon. 

August Carnelian .. Reuben. 

September Chrysolite Asher. 

October Beryl Joseph. 

November Topaz ". Simeon. 

December Ruby Judah. 

Artists  have  made  certain  changes  in  some  of  the  gems 
corresponding  to  the  months,  and  the  tribes  represented 
in  the  Urim  and  Thummim ;  they  consider  May  to  be  repre- 
sented by  emerald : 

June by  Chalcedony,  Onyx,  or  Agate  ; 

July CarneliarT ; 

August Sardonyx  ;  « 

October Aquamarine  ; 

December Chrysoprase,  Turquoise,  or  Malachite. 

In  the  early  ages  similar  views  were  entertained  in  the 
East,  and  many  of  them  are  yet  prevalent.  The  Persians 
believe  that  spinelle  affords  joy,  and 'protects  them  against 
bad  dreams.  The  Indians  believe  in  the  efficacy  of  large 
diamonds  to  bring  them  back  to  their  families.  (The  Rajah 
of  Mattan,  a  district  of  Western  Borneo,  possessed  a. dia- 
mond of  367  carats.)  The  ruby  is  esteemed,  in  the  East, 
as  a  talisman,  Avhich  is  never  shown  willingly  to  friends ; 
it  is  considered  ominous  if  it  contains  any  black  spots.  The 
Chinese,  on  the  contrary,  present  the  same  stone  as  a  testi- 
mony of  friendship.  The  Peruvians  adore  the  emerald  as 


150  A  POPULAR  TREATISE  ON  GEMS. 

their  deity.  Many  of  these  fabulous  notions  were  probably 
brought  from  the  East  to  Europe;  for  we  find,  in  the 
middle  ages,  similar  views  entertained  by  Marbodus,  Bishop 
of  Rennes,  who  wrote  a  book  on  the  miraculous  powers  of 
gems.  The  twelve  Apostles  were  likewise  represented 
symbolically  by  gems,  and  they  were  called  "  the  Apostle 
gems;"  as — 


Jasper for  St.  Peter ; 

Sapphire * St.  Andrew ; 

Chalcedony St.  James  ; 

Emerald St.  John  ; 

Sardonyx St.  Philip; 

Carnelian St.  Bartholomew ; 

Chrysolite ; St.  Matthew  ; 

Beryl St.  Thomas  ;  ^ 

Chrysoprase.. St.  Thaddeus  ; 

Topaz St.  James  the  Less  ; 

Hyacinth St.  Simeon  ; 

Amethyst St.  Matthias. 


The  ancients,  induced  by  the  beauty  of  gems — the  pure 
and  deep  color  of  the  emerald,  the  vivid  and  high  lustre 
of  the  diamond,  and  the  agreeable  reflections  of  the  opal 
— had  commenced  using  them  as  ornaments  and  jewelry, 
and  they  took  pains  to  adapt  them  to  their  purposes. 
Although  they  did  not,  in  'those  times,  understand  the  art 
of  cutting  and  polishing  them  as  practised  at  the  present 
time,  yet  they  endeavored  to  work  them  into  all  possible 
shapes,  by  rubbing  off  the  corners,  or  polishing  the  natural 
faces.  They  generally  fixed  the  gems  on  strings ;  they 
also  tried  to  carve  figures  representing  deities,  religious 
costumes,  historical  events,  exploits  of  celebrated  generals, 
or  the  heads  of  great  men. 


SCULPTURE  IN  GEMS.  151 


SCULPTURE  IN  GEMS. 

The  art  of  carving  was  well  known  to  the  ancients,  and 
those  stones  were  called  gems,  in  the  proper  sense  of  the 
word,  which  had  figures  or  letters  engraved  on  them  in  a 
very  small  compass,  the  workmanship  of  which  we,  at  this 
day,  cannot  help  admiring. 

Gem-sculpture,  or  the  glyptic  art  (or  lithoglyptics),  is  the 
art  of  representing  designs  upon  precious  stones,  either  in 
raised  work  (cameos)  or  by  figures  cut  into  or  below  the 
surface  (intaglios).  The  first  were  most  natural  to  the 
rising  art,  and  were  used  as  seals ;  whereas  the  latter  were 
used  as  ornaments,  for  which  the  most  precious  materials 
were  employed,  according  to  the  state  .of  the  art.  They 
did  not  understand  engraving  on  diamonds,  or  many 
other  gems :  they  employed  only  the  softer  stones,  the 
common  precious  stones,  such  as  earn  eh*  an,  onyx,  jasper, 
&c. ;  they  also  used  paste,  or  artificial  colored  glass  compo- 
sition, for  their  engravings.  Their  mode  of  working  was 
very  simple :'  the  polishers  prepared  then*  stones  on  a  plate, 
by  means  of  the  powder  of  harder  stones,  either  round, 
oval,  flat,  or  in  shield  form,  according  to  the  designed  sub- 
ject, and  then  left  to  the  sculptors  the  subject  of  the  en- 
graving, which  was  done  by  means  of  iron,  or  diamond 
splinters  mounted  in  iron.  It  was  not  until  the  year  1500 
that  Ambrosius  Caradossa  first  discovered  the  method  of 
cutting  the  diamond.  He  prepared  the  figure  of  a  patriarch 
for  Pope  Julian  n.  He  also  discovered  the  first  traces  of 
sculpture  among  the  Jews,  Persians,  and  Egyptians.  In 
the  traditions  of  the  holy  Scriptures,  Moses,  for  instance, 
had  the  names  of  the  twelve  tribes  of  Israel  engraved  on 
the  gems  used  by  the  high-priest.  Solomon  possessed  a 
seal :  Alexander  presented  his  seal  to  Perdicas.  Augustus 
had  a  sphinx  engraved  on  his  seal ;  but  the  Indians  and 


152  A   POPULAK   TREATISE    ON    GEMS. 

Persians  engraved  mostly  mythological  animals  or  priests 
in  their  gems ;  the  Egyptians,  beetles,  which  they  adored, 
and  which  are  called  the  scarabsei.  "  Abraxes"  were  the 
oldest  gems,  which  had  the  representation  of  fantastical 
animals,  with  the  above  word  in  the  Greek  language,  en- 
graved on  them. 

The  Phenicians,  Hetrurians,  and  Greeks  learned  the 
art  of  carving  from  the  Egyptians ;  and  from  them  it  was 
carried  to  the  Romans,  where  it  was  lost,  in  the  decline 
of  the  empire,  in  the  fifteenth  century,  under  the  Popes 
Martin  V.  and  Paul  II.  The  art  was  revived  again  by 
some  fugitive  Greeks  in  Italy.  Great  merit  is  also  due  to 
the  Medicians  for  the  revival  of  the  art ;  and  Giovani  was 
considered  the  first  in  Italy.  The  talisman,  or  carved 
gems  bearing  Arabian  letters,  belong  to  those  times. 
Precious  stones  with  layers  and  veins,  or  such  as  onyx,  sar- 
donyx, &c.,  were  employed  by  the  ancients,  with  great 
skill,  in  the  carving  of  cameos,  where  we  find  the  head  of 
one  color,  and  the  hair  and  dress  of  a  different  color  carved 
out  of  the  other  layer  of  the  stone.  Very  often  the  sub- 
jects were  mythological,  and  this  mode  of  carving  or  sculp- 
ture has  been  imitated  by  modern  artists.  It  is  sometimes 
with  difficulty  that  Ave  are  enabled  to  distinguish  the  an- 
cient from  the  modern  works,  and  the  only  authentic 
authority  for  the  antiquity  of  the  cameo  or  intaglio  is  its 
excavation  from  ancient  monuments,  except  in  a  few  in- 
stances, where  we  may  be  able  to  judge  by  comparison  of 
the  difference  in  antiquity ;  by  observing  whether  or  not 
they,  are  unnaturally,  or  stiffly  done;. have  large  heads, 
hands,  and  feet,  or  stiff  streaks  resembling  the  hair,  &c. 
We  find  that  some  gods,  representing  the  peculiar  gems 
(such  we  see  all  sculptures  of  Bacchus,  and  what  relates  to 
him),  were  executed  in  amethyst,  being  the  color  of  wine ; 
and  all  nymphs,  Neptune,  or  fish,  in  aquamarine,  <fec.,  the 


ON   GRINDING. 


153 


color  of  water.  We  find  also,  in  Germany,  traces  of  sculp- 
ture in  the  fourteenth  and  sixteenth  centuries ;  the  oldest 
known  artist,  Daniel  Engelhard,  at  Kuremburgh,  died  in 
1552  ;  also  Lucas  Kilian;  and  the  best  artist,  Nater,  died 
in  1705.  England  and  France  had  likewise  very  distin- 
guished artists  in  carving.  A  full  history  of  gem-sculpture 
may  be  found  in  the  Encyclopedia  Americana,  pp.  403-405. 


ON   GRINDING. 

The  art  of  grinding  gems  is  of  more  modem  origin;  it 
consists  in  cutting  the  gems,  and  other  precious  stones,  into 
figures,  bounded  by  many  planes,  and  by  polishing  the 
faces  thus  formed,  increasing  their  lustre,  transparency,  and 
other  valuable  properties.  This  constitutes  the  work  of 
the  lapidary.  In  the  year  1290  a  society  of  lapidaries  was 
formed  at  Paris,  and  in  1385  there  were  diamond-cutters  at 
Nuremburgh  ;  but  it  Avas  not  until  1456  that  Ludwig  Yan 
Bergen  invented  the  art  of  polishing  the  diamond  with  its 
own  powder;  gems  were  then  cut  according  to  mathe- 
matical principles;  the  art  has  been  brought,  in  modern 
tunes,  to  the  greatest  perfection.  There  is  a  great  difference 
in  gems  (which  are  mostly  procured  from  the  Indies  in  a 
rough  or  polished  state),  easily  to  be  detected  by  their  im- 


Fig.  1. 


Fig.  1  a. 


154 


A  POPULAR  TREATISE  OX  GEMS. 


perfections.  The  Indians  look  more  upon  the  size  of  the  stone 
than  upon  the  cut,  which  is  generally  irregular  and  devoid 
of  symmetry.  We  observe  this  in  the  two  celebrated  dia- 
monds of  the  Shah  of  Persia,  the  Dariainur — brilliant  sea 
— (figs.  1  and  1  a),  and  the  Kuinur — brilliant  mountain — 
(figs.  2  and  2  a)",  the  one  is  worn  on  the  left  arm,  and  the 
other  on  the  right  knee. 


Fig.  2. 


/ 


Fig.  2  a. 

By  looking  at  the  subjoined  representation  of  the  dia- 
mond belonging  to  the  crown  of  France  (figs.  3  and  3  «), 
which  weighs  one  hundred  and  thirty-six  and  a  quarter 
carats,  is  fourteen  lines  long,  thirteen  and  a  quarter  lines, 
broad,  and  nine  and  a  quarter  lines  thick,  and  which  is 
known  by  the  name  of  liegent,  we  can  more  distinctly  dis- 
criminate the  irregular  and  unmathematical  cut. 

The  gem-grinders  are  divided  into  three  classes:  first, 


OX   GELSTDING.  155 


Fig.  a  .      ^        Fig.  So. 

the  diamond ;  second,  the  gem ;  and  third,  the  jewelry 
grinders. 

The  diamond  grinder  divides  his  work  into — <7,  slitting 
or  cleaving ;  #,  cutting ;  c,  grinding ;  and  d,  polishing. 

Before  operating  upon  diamonds,  some  preliminary  ex- 
periments as  to  their  soundness  are  made:  for  very  fine 
imperceptible  fissures  may,  at  the  end  of  a  laborious  grind- 
ing, terminate  either  in  cracking  or  spoiling  the  stone. 
An  examination  for  this  purpose  is  made  in  one  of  the  two 
following  modes  :  either  the  diamonds,  or  any  other  gems 
to  be  examined,  are  steeped  in  Canada  balsam,  or  in  oil  of 
sassafras  or  aniseed,  in  which  fluid  they  are  well  turned 
around,  whereby  the  minutest  fissure,  on  account  of  its 
changed  refraction  of  light  from  that  of  the  rest  of  the 
stone,  may  be  detected ;  or  the  diamond  is  exposed  to  a 
great  heat,  and  is  then  thrown  into  water,  when  it  will 
crumble  to  pieces  should  any  cracks  exist  within  it.  The 
diamond,  although  the  hardest  of  all  known  substances, 
may  yet,  with  facility,  be  cloven  with  steel  tools,  the  blow 
being  properly  applied.  The  octahedrons  are  best  fitted 
for  cleaving :  they  are  generally,  however,  somewhat 
rounded,  and  in  order  to  cleave  them,  those  planes  which 
are  to  be  cloven,  are  left  bare,  and  the  rest  is -coated  with 
a  •composition  of  resin  and  brick-dust ;  the  bare  plane  is 
now  rubbed  with  another  sharp-edged  diamond  until  a 


156  A   POPULAR    TREATISE    ON    GEMS.      ' 

furrow  is  obtained,  which  will  render  the  planes  suitable 
for  applying  the  cleaving  instrument,  and  this  operation  is 
repeated  with  every  plane.  Diamonds  that  are  not  fit  for 
being  cloven,  are  called  by  the  Dutch,  "  divelsteene"  (devil- 
stones).  Large  diamonds,  which  are  too  precious  to  be 
expose  to  a  dangerous  cleavage,  are  sawed  by  means  of  a 
fine  steel  wire,  moistened  with  oil  and  diamond-powder. 

The  rough-cut  diamonds,  as  they  are  brought  from  the 
Indies,  are  called  laborer. 

Mr.  M awe  gives  the  following  description  of  the  art  of 
cutting  -and  polishing  diamonds  : 

"  The  object  of  cutting  and  polishing  the  diamond  is 
twofold : 

"  First,  to  divide  the  natural  surface  of  the  stone  in  a 
symmetrical  manner,  by  means  of  a  number  of  highly- 
polished  polygonal  planes,  and  thus  to  bring  out  to  the 
best  advantage  the  wonderful  refulgence  of  this  beautiful 
gem ;  and,  secondly,  by  cutting  out  such  flaws  as  may 
happen  to  be  near  the  surface,  to  remove  those  blemishes 
that  materially  detract  from  its  beauty,  and  consequently 
from  its  value. 

"  The  removal  of  flaws  is  a  matter  of  great  importance: 
for,  owing  to  the  form  in  which  the  diamond  is  cut,  and  its 
high  degree  of  refrangibility,  the  smallest  fault  is  magnified, 
and  becomes  obtrusively  visible  in  every  facet.  For  this 
reason,  also,  it  is  by  no  means  an  easy  matter,  at  all  times, 
to  ascertain  whether  a  flaw  is"  or  is  not  superficial ;  and  a 
person  with  a  correct  and  well-practised  eye  may  often  pur- 
chase, to  great  advantage,  stones  which  appear  to  be  flawed 
quite  through,  but  are,  in  fact,  only  superficially  blemished. 

"The  first  thing  the  artist  has  to  do,  when  a  rough  dia- 
mond is  put  into  his  hands,  is  to  examine  carefully  in  what 
direction  the  stone  may  be  cut,  so  as  to  afford  the  greatest 
breadth,  or  spread,  as  it  is  technically  termed,  after  the 


ON  GRINDING.  157 

flaws,  if  any,  shall  have  been  taken  out.  f  So  great  a  stress 
is  laid,  by  modern  fashion,  on  the  superficial  extent  of  a 
brilliant,  that  the  old  rules  of  proportioning  its  dimensions 
are  now  nearly  obsolete:  the  best  cutters  have  entirely 
discarded  the  use  of  measures,  and,  in  forming  the  facets, 
trust  wholly  to  an  accurate  and  well-practised  eye.  The 
direction  being  determined  on,  the  artist  must  he  well 
aware  which  are  the  hard  points  and  which  the  soft  ones  ; 
the  former  being  those  solid  angles  of  the  original  octahe- 
dron, which  it  is  necessary  to  cut  directly  across,  and  the 
latter  those  solid  angles  which  are  to  be  obliquely  divided. 
A  degree  of  force  which  may  be  safely  applied,  and  is  even 
requisite  in  making  a  section  through  the  former,  will  be 
very  apt  to  flaw  and  tear  up  the  laminaB  when  applied  to 
latter.  On  these  accounts  it  probably  is,  that  the  fatiguing 
and  even  painful  process  of  performing  this  part  of  the 
business  by  hand,  is  not  yet  superseded  by  the  use  of 
machinery. 

"  These  preliminary  matters  being  settled,  the  diamond 
is  imbedded  in^a  strong  cement,  fixed  at  the  end  of  a  stout 
spindle-shaped  stick,  about  a  foot  long,  with  that  portion 
only  projecting,  the  removal  of  which  is  to  form  the  first 
facet.  The  instrument  employed  for  this  purpose  is  another 
diamond,  fixed  in  a  stick  similar  to  the  former,  with  one  of 
the  solid  angles  projecting.  In  order  to  collect  the  powder 
and  shivers  that  are  detached  during  the  process,  the  cut- 
ting is  performed  over  a  strong  box,  four  or  five  inches 
square,  furnished  with  a  false  bottom  perforated  with  ex 
cessively  minute  holes,  in  order  to  sift,  as  it  were,  the  dust 
from  the  shivers;  and  also  with  two  upright  iron  pegs, 
fixed  on  the  sides,  for  the  workman  to  support  and  steady 
his  fingers  against,  while  with  a  short  repeated  stroke, 
somewhat  between  scratching  and  cutting,  he  is.  splitting 
off,  or  more  laboriously  wearing  away  the  diamond  in  that 


158  A  POPULAR  TREATISE  ON  GEMS. 

part  where  the  facet  is  to  be  placed.  This  being  done,  the 
cement  is  softened  by  warming  it,  and  the  position  of  the 
diamond  is  changed,  in  order  to  bring  a  fresh  part  under 
the  action  of  the  cutting-diamond.  When,  in  this  slow 
laborious  way,  all  the  facets  have  been  placed  upon  the  sur- 
face of  the  diamond,  the  cutting  is  completed.  The  stone, 
if  examined  by  a  moderate  magnifier,  now  presents  ragged, 
rough  edges;  and  a  broken,  foliated  surface,  with  a  glisten- 
ing lustre  on  those  facets  that  are' nearly  in  the  direction 
of  the  natural  lamina?,  and  on  the  other  facets  a  more  even 
surface,  but  of  a  dull  opaque  grayish-white  color. 

"  The  shape  of  many  diamonds  is  so  irregular,  that  it  is 
necessary  to  remove  pieces  of  considerable  magnitude  in 
order  to  bring  them  to  a  form  proper  for  cutting.  Where 
the  lines  of  these  proposed  sections  coincide  with  the 
natural  lamellar  structure  of  the  stone,  the  workman  has 
recourse  to  the  delicate,  and  perhaps  somewhat  hazardous, 
operation  of  splitting  the  diamond,  by  which  a  double  ad- 
vantage is  obtained.  In  the  first  place,  there  is  a  great 
saving  of  time ;  and  in  the  second  place,  the  slices  or  shivers 
are  themselves  sufficiently  large  to  admit  of  being  cut  and 
polished.  The  method  of  splitting  is  made  a  great  mystery ; 
thus  much,  however,  may  be  mentioned,  that  when  the 
direction  in  which  ^the  section  is  to  be  made  has  been  deter- 
mined on,  it  is  marked  by  a  very  fine  line,  cut  by  the 
point  of  another  dfamond :  the-  stone  is  afterwards  fixed 
by  strong  cement  in  the  proper  position,  in  a  block  of  wood, 
and  then,  by  the  application  of  a  due  degree  of  force,  the 
section  is  effected. 

"  The  diamond  being  thus,  by  the  joint  action  of  split- 
ting and  cutting,  brought  to  the  required  form,  the  next 
object  is  to  polish  the  facets,  and  at  the  same  time  to 
redress  any  little  inequalities  that  may  have  taken  place  in 
the  cutting.  The  polishing-mill  is  an  extremely  simple 


fill 


OX   GRINDING.  159 

machine,  consisting  of  a  circular  horizontal  plate  of  cast- 
iron,  fourteen  or  fifteen  inches  in  diameter,  called  a  skive, 
suspended  on  a  spindle,  and  capable  of  being  put  into  rapid 
motion  by  means  of  a  larger  wheel,  five  or  six  feet  in 
diameter,  and  turned  by  an  assistant..  From  the  centre  to 
the  circumference  of  the  iron  plate,  are  lines*  or  shallow 
grooves,  formed  by  rubbing  it  in  that  direction  with  a  fine 
grained  gritstone :  these  grooves  serve  to  retain  the  mix- 
ture of  oil  and  diamond-powder  with  which  the  plate  is 
charged.  In  order  to  keep  the  diamond  perfectly  steady 
while  the  polishing  of  each  facet  is  going  on,  the  following 
contrivance  is  had  recourse  to : — a  copper  cup,  called  a  dopp, 
about  three  quarters  of  an  inch  in  depth  and  in  width,  and 
furnished  with  a  stem  about  four  inches  long  of  stout 
copper  wire,  is  filled  with  plumbers'  solder,  which  also  pro- 
jects in  a  conical  form  beyond  the  rim  of  the  cup  :  in  the 
apex  of  this  cone,  the  solder  being  softened  by  heat,  the 
diamond  is  imbedded  with  one  of  the  facets  projecting. 
The  stem  of  the  cup  is  now  put  into  very  powerful  pincers, 
which  screw  up  with  a  nut  and  a  wrench  or  lever,  and  thus 
hold  it  perfectly  tight.  The  handles  of  the  pincers  (made 
of  wood,  and  called  tongs)  are  broad,  and  terminate  in  two 
feet,  about  an  inch  high,  so  that  when  laid  horizontally, 
they  are  supported  exactly  as  a  pair  of  candle  snuffers  are, 
the  studs  fixed  to  the  handles  of  the  snuffers  representing 
ing  the  legs  of  the  pincers,  and  the  single  stud  near  the 
point  of  the  snuffers  representing  the  inverted  copper  cup 
holding^the  diamond  is  placed  on  the  plate,  the  pincers  rest- 
ing on  their  legs  on  the  wooden  bench  or.  table  that  sup- 
ports the  plate,  and  pressing  at  the  same  time  against  an 
upright  iron  peg ;  the  broad  part  of  the  pincers  between 
the  legs  and  the^diajnond,  is  then  loaded  with  weights, 
both  to  steady  the  machine,  ^ind  to  increase  the  pressure  of 
the  diamond  against  the  skive.  Matters  being  thus  ad 


160  A    POPULAR   TREATISE    OX    GEMS. 

justed,  a  little  oil  and  diamond  powder  is  dropped  on  the 
plate,  it  is  set  in  motion  at  the  rate  of  about  two  hundred 
revolutions  in  a  minute,  and  the  process  of  grinding  down, 
and  at  the  same  time  of  polishing,  is  begun.  The  diamond 
is  taken  up  and  examined  from  time  to  time,  and  is  adjusted 
so  as  to  give -the  facet  its  true  form.  The  heat  occasioned 
by  the  friction  is  at  all  times  pretty  considerable,  and  when 
the  pincers  are  heavily  laden,  it  occasionally  increases  to 
such  a  degree  as  to  soften  the  solder  and  displace  the  dia- 
mond. This  is  a  serious  accident,  frequently  occasioning  a 
flaw  in  the  diamond,  and  always  tearing  up  the  surface  of 
the  skive,  so  as  to  damage  it  very  considerably.  There  is 
room  on  the  skive  for  three  or  four  diamonds  at  the  same 
time ;  and  to  give  each  its  proper  share  of  attention,  is  as 
much  as  one  person  can  well  manage.  The  completion  of 
a  single  facet  often  occupies  some  hours." 

The  polish  is  often  produced  by  rubbing  the  diamond 
with  a  cloth  or  bare  hand.  The  form  which  the  gems  have 
to  receive  from  the  lapidary  varies  according  to  the  condi- 
tion of  the  stones;  and  the  skill  of  the  artist  consists  in  the 
right  selection  of  a  form  which  shall  correspond  with  the 
natural  structure  of  the  gems.  A  good  cut  has  the  greatest 
influence  on  the  lustre  and  beauty  of  gems ;  the  colorless 
and  limpid  gems,  for  instance,  require  a  different  form  from 
those  which  have  a  play  of  colors.  With  a  diamond,  the 
form  must  correspond  as  much  as  possible  with  its  natural 
or  original  shape,  in  order  to  save  the  great  trouble  of 
grinding,  and  the  waste  thereby  produced.  Transparent 
gems  ought  not  to  be  cut  too  thick ;  the  rays  of  light 
might  otherwise  be  refracted  too  much,  or  prevented  from 
penetrating  through  them  at  all :  in  the  first  instance,  the 
lower  facets  do  not  act  in  correspondence#with  the  upper, 
and  the  rays  are  much  distributed  before  reaching  the  eye. 
Gems  of  such  description  are  called  clotty.  On  the  other 


FOKMS    OF   THE   DIAMOND.  161 

hand,  if  the  gems  are  too  thin,  their  beauty,  elements,  and 
general  value  are  likewise  diminished.  There  is  a  definite 
proportion  of  thickness  to  the  breadth  of  colorless  or  limpid 
gems,  whereas  the  cut  of  the  colored  gems  -depends  upon 
the  intensity  of  the  color. 

„      POEMS    OF   THE   DIAMOND. 

Diamonds  were  formerly  cut  according.to  their  natural 
form,  and  mostly  in  the  planes  of  the  octahedron.  They 
were  called  then  point  diamonds  (pierres  de  nature,  oi- 
pointes  ingenues). 

The  following  forms  are  now,  more  or  less,  adopted  by 
the  Dutch  and  English  diamond-cutters : 

A..  The  3rittiant.  This  cut  displays  to  greatest  advan- 
tage the  lustre  of  the  diamond :  it  may  be  considered  as 
obtained  by  two  truncated  pyramids,  united  together  by  one 
common  base,  the  upper  pyramid  being  much  more  deeply 
truncated  than  the  lower.  It  is  formed 
— a,  of  the  crown,  or  that  part  of  the 
stone  which  remains  visible  after  the 
stone  is  mounted ;  b,  the  collet,  or  lower 
part ;  c,  the  girdle,  or  the  common  base 
for  the  crown  and  eollet ;  d,  the  table,  the  plane  which  is 
formed  by  the  truncature  of  the  upper  pyramid ;  e,  the 
bisel,  that  space  which  lies  between  the  girdle  and  table ; 
and  f,  the  collet-side,  the  space  between  the  girdle  and 
collet.  The  English  lapidaries  cut  the  girdle  sharp,  where- 
as the  Dutch  leave  it  broad :  the  crown  amounts  to  one 
third,  and  the  collet  to  two  thirds  of  the  whole  height  of 
the  diamond ;  the  tafole  amounts  to  four-  ninths  of  the 
diameter  of  the  brilliant,  whereas  the  collet  only  needs  one 
fifth  of  the  size  of  the  table.  The  table  and  collet  are 
regular  octagons,  and  the  facets  occupied  by  the  bisel  are 


162  A   POPULAR   TREATISE   ON   GEMS. 

eight  lozenges,  with  twenty-four  triangles,  and  are  called 
the  star-facets  /  the  facets  occupied  by  the  collet-side  are 
four  irregular  pentagons,  alternating  with  as  many  irregular 
lozenges,  radiating  from  ^the  collet  as  a  centre,  and  are 
bordered  by  sixteen  triangular  facets  adjoin- 
ing the  girdle,  and  are  generally  called  the 
pavilion  or  cro'ss  facets.  According  to  the 
number  of  facets,  the  brilliants  receive  their 
names,  either  of  double  or  treble  brilliant :  the 
double  brilliant  is  surrounded  by  two  rows  of 
facets  on  the  bisel,  which  are .  triangular,  and 
meet  each  other ;  the  treble  brilliant  has  fifty- 
eight  planes,  fifty-six  facets,  table  and  collet,  thirty-two 
facets  of  which  are  in  the  bisel  in  three  rows ;  the  star  aud 
pavilion  facets  are  triangular,  the  intermediate  ones  are 
four-sided,  -and  on  the  collet-side  are  twenty-four  facets. 

The  English  double  brilliant  consists  of  twenty-four 
facets,  table  and  collet,  sixteen  of  which  terminate  in  the 
form  of  a  star  in  the  bisel. 

Brillionets,  or  half-brilliants,  are  those  diamonds,  the 
spread  of  which  is  too  great  in  proportion  to  their  depth, 
and  the  crown  is  only  cut  like  a  brilliant,  but  the  collet-side 
is.  wanting. 

•  J5.  The  Hose-Diamond  has  a  crown, 
but  no  collet ;'  it  is  formed  of  equilateral 
triangles,  and  consists  of  two  rows  of 
three-sided  facets  ;  those  on  the  girdle 
are  pavilion,  and  the  others  star  facets. 
But  there  are  variations  in  the  number  of 
facets :  the  Dutch  roses  have  eighteen  pavilion  and  six  star 
facets;  others  have  six  pavilion  aijd  six  star  facets,  or 
twelve  pavilion  and  six  star  facets ;  and  some,  also,  have 
twenty-four  three-sided  pavilion  and  twelve^  star  facets. 
The  rose-diamond  is  only  that  diamond,  the,  proportion  of 


FORM    OF   GEMS.  163 

whose  breadth  to  its  depth  is  too  much  extended,  and 
which  would  not,  without  ranch  loss,  make  a  good  brilliant. 
There  are  fragment  rose-diamonds,  which  are  very  small, 
and  ear-drop  roses. 

C.  The  Table-Diamond  is  that  stone  which 
is  very  flat  and  of  little  depth,  and  which  re- 
flects but  little  lastre.     They  have  a  table  with 
four  planes  and  eight  facets,  and,  in  order  to 

make  the  best  of  their  lustre,  they^eceive  a  brilliant  cut. 

D.  The  Bastard- Diamond  is  that  diamond  whose  cut 
is  mixed  up  from  the  above  forms. 

There  are  a  few  more  forms  given  to  those  diamonds 
which  are  found  unfit  for  any  of.  the  above  cuts,  such  as 
the  thick-stones,  the  portrait-diamonds,  the  sen  ail-diamonds, 
which  are,  however,  all  unfit  for  the  above  cuts. 

FORM   OF   GEMS. 

The  gem  lapidary  occupies  himself  not  only  with  grind- 
ing the  common  and  rare  gems,  but  also  pastes,  &c.  He 
uses  likewise  wheels,  but  of  different  material  from  those 
for-diamonds.  His  wheels  are  either  of  copper,  if  for  very 
hard  stones,  or  of  lead  or  pewter  for  softer  stones ;  he  has 
likewise  polishing  wheels.  If  a  wheel  is  too  soft  for  very 
hard  stones,  he  cuts  furrows  in  it,  which  are  then  filled  out 
with  rotten-stone  or  tin-ashes ;  or  if  very  hard  stones,  such 
as  sapphire,  .are  to  be  ground,  the  diamond  powder  is 
used  for  the  same.  Tin  wheels  are  used  for  hard  stones  ^ 
water,  or  oil  of  vitriol,  is  used  for  moistening  the  wheels. 
The  gems  (in  order  to  grind  them  or  to  give  their  facets) 
are  cemented  into  a  handle,  at  the  end  of  which  is  a 
composition  of  resin  and  brickdust.  Particular  attention 
is  required  in  grinding  the  colored,  gems,  as  the  greatest 
effect  may  be  produced  by  their  "thickness ;  pale-colored 
gems  require  to  be  left  thicker  .than  darker  ones ;  on  the 


164  A  POPULAR  TREATISE  ON  GEMS. 

other  hand,  they  ought  not  to  be  left  too  thick,  as  they 
will  appear  too  dark,  and  thereby  'lose,  their  lustre.  The 
same  proportion  in  the  manner  of  cutting  the  crown  and 
collet  of  the  colored  gems  has  to  be  observed  as  with  the 
brilliant  ;  namely,  the  crown  ought  to  be  one  third  and  the 
collet  two  thirds  in  size  of  the  depth  of  the  whole  stone;  if 
the  gem  be  of  a  pale  color,  the  collet  ought  to  be  three 
fourths  of  the  size  ;  and  if  of  a  darker  color,  much  less  ;  the 
table  of  those  colored  g^ns  which  require  to  be  heightened 
ought  to  be  waved  somewhat,  whereas  it  ought  to  be  even 
in  darker  gems.  The  forms  received  by  the  colored  gems 
in  cutting  resemble,  in  many  instances,  those  of  the  dia- 
mond; but  the  following-are  the  additional  ones  they  re- 
ceive, according  to  the  nature  of  the  shape  and  color  of  the 
stone  : 

A.  The  Step  or  Pavilion  cut.  The  planes, 
which  are  long  and  small,  decrease  towards 
the  table  and  collet,  and  terminate  in  steps  ; 
the  crown  has  usually  two,  and  the  collet  four 
or  five  facets  on  each  side;  the  form  of  the 
stones  may  be  of  four,  six,  eight,  or  twelve  sides,  or  nray 
be  long  or  round.  This  cut  is  particularly  applicable  to 
colored  gems,  as  it  reflects  the  light  in  a  high  degree,  by 
which  the  play  of  color  is  much  raised  ;  and  it  is  at  all 
events  to  be  preferred  in  the  collet  of  colored  gems,  even' 
to  those  brilliants  in  pavilion  :  the  crown  may  be  of  any 
form  whatever. 


JB.  The  Mixed  facet  cut-  is  a  com- 
pound of  Brilliant  and  pavilion  cuts,  the 
first  being  on  the  crown  ;  it  is.  a  very  fa- 
vorite cut  for  colored  gems,  and  con- 
tributes much  in  raising  'the  lustre. 


FOKM    OF    GEMS.  165 

C.  .The  Elongated  Brilliant  facet  cut, 
which,  if  the  brilliant  facets  are  on  the 
crown   elongated,  and  the   collet   has   a 
pavilion  cut,  is  very  appropriate  to  long 
and  thin  stones. 

D.  The  Table  cut,  having  either  an  uneven  or 
conchoidal  table,  with  one  or  two  rows  of  facets, 
in  a  circular  form,  around  it :  a  very  useful  form 
for  seal-stones. 

E.  The  Double  facet  cut,  the  crown  hav- 
ing two  rows  of  facets,  and  the  collet  the 
pavilion  form;  this  cut  is  well  adapted  to 
such  stones  as  require  the  concealment  of 
any  faults,  flaws,  or  fissures. 

F.  The  Cabochon  cut,  is  either  flat,  convex,  or  double- 
convex — that  is,  arched ;  it  may  be  on  both 

sides,  or  only  on  one.  This  cut  is  particularly 
applicable  for  semi-transparent  gems,  or  those  which  display 
their  peculiar  colors,  such  as  the  opal,  moonstone,  &c. ;  or 
coUect  the  light  in  a  small  space,  on  one  or  several  points, 
according  to  the  convexity  they  have  received.  The  cabo- 
chon  cut  may  have  one,  two,  or  more  rows 
of  facets,  and  opaque  stones  receive  with  ad- 
vantage the  facets  over  the  whole  surface. 
Garnets,  for  instance,  which  are  generally  of 
a  dark  color,  are  cut  en  cabochon,  the  lower 
plane  excavated  in  a  circular  form,  and  the  upper  plane  all 
around  with  facets.  -Other  gems,  the  interior  faults  of 
which  cannot  be  concealed,  may  be  improved  by  this  cut, 
giving  them  more  transparency,  vividness  of  color,  and  a 
greater  degree  of  fire. 

A  judicious  choice  of 'the  form  in  which  any  particular 
gem  shah1  be  cut,  depends  on  the  skill  and  discrimination 
of  the  artist. 


166  A  POPULAR  TEEATISE   ON   GEMS. 


COMMON   LAPIDAKT. 

Such  common  precious  stones  as  are  suitable  to  be  cut 
for  snuff-boxes,  rings,  grinding  mortars,  seals,  and  ear- 
rings, are  wrought  by  the  common  lapidary,  by  means  of 
copper  or  iron  wheels  revolving  vertically.  The  tools  are 
generally  of  iron,  and  sometimes  brass ;  some  are  flat  like 
chisels,  gouges,  ferrules,  and  some  others  have  coriicular 
heads.  The  polish  is  given  with  rotten-stone,  on  a  tin  plate, 
or  with  crocus  martis,  on  a  wooden  plate  covered  with  felt. 
The  cuts  applied  by  the  workmen  are  either  even,  cup-shell 
form,  excavated,  elevated,  or  quite  simple ;  facets  are  not 
used  by  him. 

Mr.  Mawe  describes  a  lapidary's  apparatus,  fit  for  pol- 
ishing minerals,  shells,  &c.,  and  which  may  be  placed  in  a 
parlor,  where  every  operation  of  polishing,  on  a  scale  suffi-' 
ciently  large,  may  be  effected,  and  pebbles  may  be  slit  of 
three  or  four  inches  diameter.  It  consists  of  the  following 
mills: 

1st.  A  lead  mill,  or  wheel,  to  be  used  with  emery  and 
water,  for  grinding  down  substances  preparatory  to  pol- 
ishing. 

2d.  A  pewter  mill,  to  be  used  with  rotten-stone  a  little 
wet,  for  polishing. 

3d.  Tin  plate,  properly  prepared,  the  edge  of  which  is 
to  be  used  with  diamond  powder,  to  slit  or  cut  hard  stones 
asunder. 

»  • 

4th.  Wood  iriills,  covered  with  leather,  &c.,  for  polishing 
marble,  alabaster,  shells,  or  other  soft  substances. 

ENGBAVING. 

The  value  of  many  precious  stones  is  increased  by  en- 
graving them.  The  common  gems  have,  for  several  centu- 


ENGRAVING.  167 

ries,  been  used  in  heraldry.  In  Italy,  Germany,  and  Eng- 
land, we  find  the  coat  of  arms  of  distinguished  or  noble 
families  engraved  on  stone.  The  machine  used  for  such 
purposes  is  like  that  of  the  i  glass  cutters,  with  this  differ- 
ence, that  finer  and  harder  instruments,  and  sometimes 
diamond  splinters,  are  required  for  -this  work.  Before  the 
stone  can  be  cut  or  engraved,  its  surface,  after  having  re- 
ceived the  proper  shape  and  form  required,  is  rubbed  with 
emery,*  glass,  or  leaden  wheels.  The  artist  now  makes  his 
drawing  with  a  brass  pin,  and  executes  it  afterwards  with 
his  tools.  On  hard  stones  he  uses  diamond  powder ;  on 
soft,  emery  and  oil. 

The  engraving  of  armorial  bearings,  single  figures,  de- 
vices, &c.,  on -any  gem,  is  performed  by  means  of  a  small 
iron  wheel,  the  ends  of  the  axis  of  which  are  received  within 
two  pieces  of  iron  in  a  perpendicular  position,  that  may  or 
may  not  be  closed  as  the  operation  requires ;  the  tools  are 
fixed  to  one  end  of  the  axis,  and  .screwed  firm ;  the  stone 
to  be  engraved  is  then  held  to  the  tool,  the  wheel  set  in 
motion  by  the  foot,  and  the  figure  or  device  gradually 
formed.  '  * 

Difficult  works  are  executed  after  models  of  plaster  of 
Paris,  of  clay,  or  other  substances ;  the  polish  is  afterwards 
given  on  wheels,  provided  with  brushes  or  with  rotten-stone. 
The  semi-transparent  and  opaque  stones  are  more  used  for 
engraving  than  the  transparent  gems,  because  the  drawing 
will  not  show  distinctly  through  them,  on  account  of  the 
great  refraction  of  light ;  the  same  is  the  case  with  irides- 
cent or  shining  stones.  The  engravings  are  generally  bas- 
relief  or  raised ;  those  having  layers  are  mostly  preferred 
for  cameos ;  for  instance,  the  onyx,  sardonyx,  and  chalce- 
dony; also  wood-opal,  which  is  constantly  exported  from 
Germany  for  the'Italian  artists  in  Rome. 


168  A   POPULAR   TREATISE    OX    GEMS. 


SAWING   AND   DRILLING   GEMS. 

Gems  and  precious  stones  often  require  to  be  sawed  in 
different  directions,  which  operation  is  performed  on  a 
machine  like  that  of  a  lapidary,  with  the  exception  of  a 
polishing  plate,  for  which  is  substituted  a  cutting  plate 
having  sharp  ends,  or  by  fastening  the  stone  on  a  stand, 
and  moving  continually  a  fine  iron  or  copper  wire  stretched 
in  a  bow,  which  is  moistened  with  emery  and  oil-.  Care 
has, 'however,  to  be  taken,  not  to  let  the  stone  grow  too 
hot,  as  the  heat  may  crack  or  make  it  spotty.  The  Chi- 
nese use  strings  spun  over  in  preference  to  the  wire,  they 
having  the  advantage  of  keeping  the  emery  sticking  to 
them,  and  of  accelerating  thereby  the  operation.  For 
drilling  gems  or  other  precious  stones,  a  diamond  set  in 
steel  is  made  use  of,  to  move  to  and  fro  by  a  bow,  or  the 
common  engraving  machine,  the  drilling  instrument  of 
which  consists  of  an  iron  point,  to  which  is  fastened  a  dia- 
mond splinter,  which  is  pressed  upon  the  stone  while'  it  is 
revolving  upon  the  plate. 

GRINDING    AND    POLISHING   MATERIALS. 

The  materials  for  grinding  and  polishing  vary  according 
to  the  hardness  of  the  gem.  The  diamond  powder  is  ob- 
tained by  grinding  real  diamonds,  which  are  unfit  for  use, 
with  each  other  in  a  hollow  cylinder  of  cast  iron,  in  which 
another  one  exactly  similar  is  used  for  the  most  costly  and 
the  hardest  gems.  Corundum,  sapphire,  topaz  powder, 
and  emery  powder,  are  commonly  used  for  grinding  and 
polishing  the  diamond.  It  is  well  to  remark  that  emery  is 
often  adulterated  by  a  mixture  of  quartz  and  oxide  of  iron, 
or  by  garnet  or  iron  powder.  Emery  fit  for  the  use  in- 
tended requires  to  be  properly  pulverized  and  levigated. 


HEIGHTENING   THE   COLOR-  OF   GEMS.  169 

According  to  Hawkins,  the  following  method  is  pursued  in 
England :  The  emery  is  pulverized  in  an  iron  mortar  and 
passed  through  different  sieves,  one  finer  than  the  other ; 
the  first  is  levigated  with  oil,  which  keeps  it  in  better 
suspension  in  water ;  according  to  the  time  in  which  the 
powder  settles,  the  different  numbers  are  obtained. 

For  polishing  the  different  precious  stOnes,  hard  and  soft 
gems,  the  diamond  powder  and  emery  are  mostly  used. 
Rotten-stone,  tin-ashes,  pumice-stone,  oxide  of  iron,  English 
jewellers'-red,  are  all  used  in  their  finest  pulverized  state. 
A  great  deal  depends  upon  the  polish  wrhich  a  gem  has  re- 
ceived ;  all  its  other  superior  qualities  being  thereby  called 
forth. 

HEIGHTENING   THE   COLOR    OF   GEMS. 

Since  color  is  one  of  those  characters  which  is  the  most 
tempting  in  the  sale  of  gems  and  jewelry,  ah1  means  are 
ployed  for  heightening  the  same,  and  covering  any  real 
defect.  Foil  of  small  thin  metallic  substances,  colored  or 
uncolored,  either  of  fine  silver  or  copper,  is  placed  under 
the  gem  in  the  back  of  the  mounting,  which  heightens  the 
color  and  lustre,  particularly  of  the  transparent  gems. 
Almost  all  gems  were  formerly  set  in  black-colored  backs, 
composed  of  burnt  ivory-black  and  gum  mastic,  but  are 
now  mostly  set  d  jour,  which  is,  leaving  the  lower  part  of 
the  stone  uncovered  in  setting,  and  only  mounting  around 
the  girdle — an  old  method,  and  very  applicable  to  perfect 
stones,  where  no  defects  require  concealment. 

Foiling  materially  heightens  the  lustre  of  gems.  The 
rose-diamond  al\*»ys  requires  it  on  account  of  its  flat  form. 
There  are  many  gems  which  would  not  produce  any  effect 
without  the  foil ;  it  is  therefore  used  whenever  a  pale  or 
impure  color  is  to  be  raised,  or  when  the'gems  are  to  be 
protected  against  dust  or  moisture  in  order  to  produce  a 

8 


170  A  POPULAR  TREATISE  ON  GEMS. 

uniform  shade  of  color ;  the  foil  forms  then  a  suitable  ap- 
plication. 

The  coloring  of  the  foil  is  generally  performed  by  the 
jewellers.  Isinglass,  first  dissolved  in  water  and  afterwards 
boiled  in  spirits  of  wine,  and  then  strained,  is  the  mass  or 
body  to  which  the  colors  are  afterwards  added,  which  are 
also  soluble  in  water. 

For  producing  a  red  color,  the  best  material  is  carmine, 
"          "  blue  "  "  litmus, 

"          "  yellow        "  "  saffron. 

To  produce  the  different  shades  and  varieties  of  color,  the 
above  are  mixed  in  different  proportions  with  each  other. 
Very  clear  stones,  such  as  chfysoprase,  carnelian,  &c.,  are 
sometimes  painted  on  the  back.  The  Paris  jewellers  are 
very  skilful  in  painting  stones  of  inferior  value  so  as  to  de- 
ceive even  professional  men ;  it  is  for  this  reason  that  gems 
when  set  ought  not  to  be  purchased ;  the  valuable  gems 
which  have  a  foil  on  their  back  are  mostly  set  in  such  a 
manner  that  they  may  be  examined  without  the  same. 
Foiled  gems  may  likewise  be  distinguished  by  holding  .the 
table  of  the  set  gem  on  the  nail  of  the  thumb  and  observ- 
ing the  passage  of  light  through  the  crown. 

In  the  East,  rubies  are  never  set  with  foil,  but  a  cavity  is 
made  in  the  lower  part  and  filled  with  finely  polished  gold, 
which  raises  their  lustre  remarkably. 

Fissures,  flaws,  or  veins,  in  the  interior  of  gems,  are 
mostly  concealed  by  the  foil,  and  when  near  the  girdle, 
are  covered  by  the  mounting. 

The  defects  of  stones  are  sometimes  concealed  by  color- 
ing the  case  with  mastic  and  ivory-black,  find  according  to 
circumstances  leaving  blank  the  spot  of  the  faulty  stone, 
or  covering  only  the  spot,  so  as  to  produce  a  uniform  color. 
Another,  and  not  unusual  method  of  concealing  fissures, 
flaws,  or  other  faults,  is  to  cut  those  stones  that  have  many 


SETTING    OF   GEMS.    .  171 

faults — the  momentary  detection  of  these  faults  being  there- 
by prevented  from  the  play  of  the  refracting  light  and  the 
lustre.  The  color  of  many  gems  is  raised  by  fire,  which 
acts  in  a  peculiar  manner  on  them ;  thus  the.  Brazilian  topaz 
assumes  a  very  fine  pale-red  color,  by  burning.  The  process 
of  effecting  this  coloring  is  very  simple,  viz  :  after  wrapping 
the  topaz  in  a  sponge,  ignite  the  same  and  keep  it  burning 
until  consumed. 

The  zircon  sometimes  assumes  a  better  color  after  having 
been  subjected  to  a  high  degree  of  heat.  Amethysts  hav- 
ing dark  spots  may  be  calcined  for  a  short  time  in  a  cruci- 
ble containing  sand  and  iron  filings,  under  which  process 
they  mostly  lose  those  faults ;  but  if  exposed  to  an  excess 
of  heat,  they  will  lose  their  color  altogether,  and  become 
as  white  as  quartz.  The  Oriental  camelian  assumes,  after 
burning,  a  fine  color,  and  in  Hindostan  those  carnelians 
which  are  found  detached  in  the  mines  are  cut  up  and 
burnt  on  the  spot.  Very  fine  cracks  are  some.times  pro- 
duced in  mounting  stones,  which  may  be  repaired  and  con- 
cealed successfully  by  means  of  garlic  juice.  When  stones 
are  broken  by  the  same  operation  they  may  be  cemented 

by  gum  mastic. 

• 

SETTING   OF   GEMS. 

The  gems  are  generally  fastened  or  set  at  the  girdle  in 
a  box  or  rim  of  metal :  limpid  and  faultless  gems  are  always 
set  d  jour,  i.  e.,  without  backs,  since  they  appear  then  to 
the  best  advantage,  and  if  the  gem  is  intended  to  display 
its  full  size  and  color,  the  djour  setting  is  only  fastened  by 
small  shanks  or  claws.  The  good  setting  of  a  gem  very 
much  increases  its  value  and  beauty.  The  material  for 
mounting  the  limpid  gems  is  silver,  which  displays  them  to 
more  advantage  than  gold.  In  order  to  increase  the  color 
or  lustre  of  large  gems,  they  are  often  surrounded  by 


1'72          A  POPULAR  TREATISE  ON  GEMS. 

smaller  gems,  such  as  small  roses,  rabies,  emeralds,  garnets, 
turquoise,  &c. 

The  jewellers'  wax  used  for  mounting  gems  is  made  of 
three  parts  rosin,  one  part  beeswax,  and  four  parts  fine 
brickdust. 

CLEANING   THE    GEMS. 

The  following  composition  I  have  found  to  be  the  best 
for  thoroughly  cleaning  gems,  particularly  when  set :  Take 
one  part  flowers  of  sulphur  and  two  parts  of  rotten-stone 
or  bone-ashes,  which,  when  mixed,  is  used  by  rubbing  it  on 
a  piece  of  buckskin,  and  with  that  and  a  stiff  hair-brush,  al- 
ternately rubbing  the  gems,  finishing  with  a  softer  skin  or 
cloth  to  remove  the  dust. 

IMITATIONS    OF    GEMS. 

Pliny  mentions  the  imitation  of  jewels  by  glass  fluxes, 
and  it  is  sufficiently  proved  that  the  ancients  were  far  ad- 
vanced in  this  art.  The  Egyptian  mummies  were  provided 
with  glass  buttons  of  green  an£  blue  color,  and  during  the 
reign  of  the  Roman  empire,  colored  glass  was  very  general ; 
and  we  find  antique  cameos  carved  in  various  colored  glass, 
representing  the  onyx ;  likewise  colored  glass  cemented 
with  real  onyx ;  but  they  never  attained  such  perfection  in 
their  art  as  to  set  at  defiance  the  skill  of  the  artist  and 
jeweller  to  distinguish  between  the  genuine  and  spurious 
ones.  The  imitation  of  gems  may  be  divided  into  three 
classes : 

A.  The  Pastes.  The  basis  of  these  imitations  is  a  fine, 
pure,  and  white  glass  composition,  called  strass,  after  its 
inventor,  Strass  of  Strasburgh,  in  the  seventeenth  century, 
who  first  conceived  the  importance  of  imitating  the  real 
gems  as  respects  their  hardness,  specific  gravity,  and  re- 


IMITATIONS    OF   GEMS.  17*3 

fraction  of  light.  He  accomplished  the  task  so  far  that  in 
many  instances,  either  all  three,  or  one  or  the  other  of  his 
objects,  were  attained.  The  strass  is  composed  of  silex 
(quartz,  flint,  or  pure  sand),  potash,  borax,  red  lead,  and 
sometimes  arsenic.  To  300  parts  of  silex  add  96  parts  pot- 
ash, 27  parts  borax  (prepared  from  the  boracic  acid),  and 
514  parts  of  white  lead,  and  1  part  arsenic;  or  according 
to  another  method,  mix  V  ounces  and  24  grains  of  quartz 
with  10  ounces  and  7J  drachms  red  lead,  3  ounces  and  6 
drachms  pure  pearlashes,  3f  J  drachms  borax,  and  12  grains 
arsenic.  The  mixture  is  put  into  a  covered  Hessian  cruci- 
ble, and  kept  at  a  great  heat  in  a  pottery  furnace  for 
twenty-four  hours.  The  longer  the  mass  is  kept  in  a  fluid 
state  the  harder  and  clearer  it  will  be  when  turned  out  and 
cooled.  This  discolored  strass  is  used  by  the  lapidaries  for 
imitating  the"  diamond,  rock-crystal,  and  white  topaz. 

For  imitating  the  colored  gems  various  colored  ingre- 
dients are  employed.  To  obtain  that  intensity-  of  color  ap- 
proaching nearest  to  the  original  gem,  it  is  experience 
alone  which  can  guide  the  manufacturer.  In  order  to  imi- 
tate the  uniform  and  intense  colors,  the  strass  coloring  in- 
gredients are  to  be  of  the  finest  powder,  and  very  intimately 
mixed;  the  mass  is  then  to  be  exposed  to  a  very  great 
heat,  and  in  that  state  left  for  nearly  thirty  hours,  so  that 
the  cooling  may  be  gradual.  Numerous  establishments  in 
Germany  and  France  are  now  engaged  in  the  manufacture 
of  the  strass  and  colored  pastes,  each  of  which  possesses 
secrets,  acquired  by  experience,  for  producing  these  articles 
in  the  greatest  perfection. 

A.  Artificial  Topaz.  Take  of  perfectly  white  strass  one 
ounce   and   six   drachms,  glass  of  antimony  thirty-seven 
grains,  and  cassius  purple  one  grain ;  or  add  to  six  ounces 
of  strass  half  a  drachm  of  crocus  martis. 

B.  Artificial  Ruby.  This  may  be  obtained,  from  the  pre- 


1*74          A  POPULAR  TREATISE  ON  GEMS. 

ceding  mixture  for  the  topaz  by  the  addition  of  eight  parts 
more  of  strass,  and  left  for  thirty  hours  in  fusion ;  when 
taken  out  and  fused  before  the  blowpipe,  it  yields  a  most 
beautiful  Oriental  ruby.  Five  ounces  strass  and  one  drachm 
oxide  of  manganese  may  be  employed  for  the  same  pur- 
pose, but  will  not  make  so  fine  a  ruby.  Or  by  calcining 
ammoniacal  alum  with  chromate  of  potash  and  lampblack, 
which  forms  the  composition  of 

97  parts  alumine, 

1  "     oxide  of  chrome, 

2  "      silica  and  lime. 

C.  Artificial  Emerald.  To  one  pound  of  strass  add  one 
drachm  of  verdigris  and  fifteen  grains  crocus  martis. 

D.  Artificial  Sapphire.   Add  to  eight  ounces  of  strass 
fifty-two  grains  pure  oxide  of  cobalt. 

E.  Artificial  Amethyst.  To  eight  ounces  of  strass  add 
thirty  grains  oxide  of  manganese,  twenty-four  grains  oxide 
of  cobalt,  and  forty  grains  cassius  purple  ;  or  to  one  pound 
of  strass,  twenty  grains  oxide  of  manganese,  and  one  grain 
oxide  of  cobalt.          • 

F.  Artificial  Aquamarine.  To  six  ounces  of  strass  add 
twenty-four,  grains  glass  of  antimony,  and  one  and  a  half 
grain  oxide  of  cobalt. 

C.  Artificial  Syrian  Garnet.  To  one  thousand  grains  of 
strass  add  five  hundred  grains  glass  of  antimony,  four 
grains  cassius  purple,  and  four  grains  oxide  of  manganese. 

Messrs.  Bouillette,  Hyrclin  &  Co.,  Rue  St.  Avaye;  Savany 
&  Mosbach,  Rue  Vaucauson,  in  Paris;  and  Henrys  &  Co.,  of 
London,  have  contributed  to  the  great  London  Exhibition, 
in  1851,  a  great  display  of  their  manufactures  in  artificial 
stones,  such  as  diamonds,  .emeralds,  sapphires,  and  pearls. 
The  latter  were  particularly  brought  to  perfection  by  Mr. 
Constant  Vales,  Rue  St.  Martin,-  Paris,  as  the  imitation 
pearls  by  that  gentleman  were  superior  to  any  thing  the 


IMITATIONS    OF    GEMS.  175 

author  had  ever  seen  before,  and  were,  to  appearance, 
quite  equal  to  the  natural  pearls. 

The  following  table,  taken  from  Booth's  Encyclopedia, 
shows  the  proportions  of  the  various  ingredients  for  the 
different  colored  pastes : 

•       Topaz.  Ruby.  Amethyst.  Garnet.  Sapphire.  Aq.  Mar.  Emerald. 

Colorless   Paste 1000   1000      1000  1000  1000  1000       1000 

Antimony  Glass 40                     ..  500  ..  7 

Oxide  of  Manganese..       ..25            8  4 

Gold  Purple 1        ..           >/•  4 

Oxide  of  Cobalt 5  ..  15  »/» 

Oxide  of  Copper ..  ..  8 

Oxide  of  Chrome . .  . .  .'.  •  •          Ys 

Colored  glass  is  also  very  frequently  cut  in  forms  and 
shapes  so  as  to  resemble  gems,  and  the  various  colors  are 
produced  by  melting  the  best  qualities  of  glass  materials 
with  the  folio  whig  oxides : 

Yellow  is  produced  by  charcoal,  antimonite  of  potassa, ' 
silver,  and  oxide  of  uranium. 

Blue,  by  oxide  of  cobalt,  and  a  mixture  of  copper  and 
iron. 

Green,  by  oxide  of  copper  or  of  chrome,  or  by  antimo- 
nite of  potassa,  litharge,  and  cobalt. 

Red,  by  gold,  suboxide  of  copper,  and  oxide  of  iron. 

Violet,  by  manganese. 

Black,  by  protoxide  of  uranium,  iridium,  platinum,  and 
by  a  mixture  of  manganese,  copper,  iron,  and  cobalt. 
White,  by  oxide  of  tin,  arsenic,  and  bone'-ashes. 

By  combining  one  or  more  of  these  oxides  various  shades 
and  hues  may  be  obtained ;  the  yellow  glass  of  antimony 
may  be  shaded  more  into  orange  by  the  use  of  a  little 
oxide  of  iron  ;  the  purple-red  of  gold  passes  into  carmine 
by  employing  silver  with  gold  ;  the  blue  of  cobalt  may  be 
shaded  into  purple  by  a  little  gold ;  into  green  by  antimony, 


176  A   POPULAR   TREATISE   ON   GEMS. 

or  other  yellow  colors ;  a  rich  grass-green  is  obtained  from 
oxide  of  chrome,  with  a  little  antimony  and  litharge ;  a 
brilliant  emerald-green  from  a  mixture  of  oxide  of  uranium 
and  nickel ;  oxide  of  nickel  alone  yields  a  hyacinth-red. 

The  Bohemian  garnet  is  prepared  by  fusing  together  100 
parts  quartz,  150  parts  red  lead,  30  parts  potash,  20  parts 
fused  borax,  5  parts  crude  antimony,  5  parts  manganese, 
and  6  parts  fulminating  gold  ground  up  with  oil  of  turpen- 
tine. 

Turquoise  is  imitated  by  oxides  of  copper  and  cobalt. 
Opal,  by  adding  oxide  of  tin  and  bone-ashes  to  the  glass,  in 
small  quantities. 

The  following  colored  pastes  were  recommended  by 
me  twenty  years  ago,  to  the  American  manufacturers  of 
colored  glass,  and  have  all  proved  successful : 

JStrass. 

This  is  the  basis  for  ah1  pastes ;  it  is  very  hard,  and  gives 
sparks  when  rubbed  on  steel. 

1  ounce  of  powdered  glass,  2  drachms  burnt  borax, 

3  drachms         "          quartz,  40  grains  of  saltpetre, 

3  «'  "          red  lead,  30        "        white  arsenic. 

This  composition  is  exposed  to  a  white  heat  in  a  covered 
crucible  for  thirty  hours. 

Ruby. 

I  ounce  of  powdered  rock-crystal         3  drachms  of  red  lead, 

or  quartz,  15  grains  of  eassius  purple, 
i  ounce  of  dried  carbonate  soda,  8        "        metallic  antimony, 

4  drachms  of  burnt  borax,  8        "        oxide  manganese. 
It        "            saltpetre, 

Or  by  taking — 

1  ounce  of  powdered  rock-crystal,       40  grains  saltpetre, 
i        "        dry  carbonate  soda,  15    "        purple  cassius, 

80  grains  of  burnt  borax,  1  drachm  of  sal  ammonia. 


IMITATIONS    OF    GEMS. 


Take— 

It  ounce  of  ground  rock-crystal, 
6  drachms  of  dry  soda, 

2  "  "    borax, 

Or  mix — 

1  ounce  of  rock-crystal, 
y        "        dry  soda, 

3  drachms    "   borax, 
It        "        red  lead, 


Sapphire. 


2  drachms  of  red  lead, 
1          "  saltpetre, 

1  grain,  of  carbonate  cobalt. 


.t  drachm  of  saltpetre, 
i  grain  of  carbonate  cobalt, 
15        "  "        copper. 


By  means  of  the  carbonate  of  copper. 


It  ounce  of  rock-crystal, 
6  drachms  of  soda, 
1          ««          borax, 


Take- 
it  ounce  of  rock-crystal, 
6  drachma  of  dry  soda, 
2          "  "    borax, 

2          "          red  lead, 


1«  ounce  of  rock-crystal, 
t        "        dry  soda, 
2  drachms  of  dry  borax, 
2  "        .  red  lead, 


9  drachms  of  rock-crystal, 
8          "  dry  soda, 

2         "  red  lead, 

1          "  saltpetre, 


It  ounce  of  rock-crystal, 
t         "        dry  soda, 
8  drachms  of  burnt  borax, 
2         "  red  lead, 

20  grains  of  saltpetre, 


1  drachm  red  lead, 
t  "  saltpetre, 
t  "  carbonate  of  copper. 


Emerald. 


1  drachm  of  saltpetre, 
20  grains  of  red  oxide  of  iron, 
10        "         green  carbonate  of 
copper. 

Green  Color. 

40  grains  of  saltpetre, 

It        "         carbonate  cobalt, 

10        "  "        chrome. 

Canary. 

80  grains  of  oxide  of  uranium, 
3        "         carbonate  of  copper, 


oxide  of  tin, 

white  b'nt  bone-ashes. 


Chrysoprase. 

2  drachms  of  white  bone-ashes, 
2  grains  of  carbonate  of  copper, 
4        "         red  oxide  of  iron, 
6        "         oxide  of  chrome. 


178  A   POPULAR   TREATISE   ON   GEMS. 


Opal. 

9  drachms  of  rock-crystal,  15  grains  of  saltpetre, 

8         "          dry  soda,  »/io        "         cassias  purple, 

2          "           burnt  borax,  Iff        "         bone-ashes, 

li          "          red  lead,  2        "         muriate  silver. 

Aquamarine. 

Is  ounce  of  rock-crystal,  1  drachm  of  saltpetre, 

1  "        dry  soda,  *    6  grains  of  red  oxide  of  iron, 

8  drachms  of  burnt  borax,  2        "         carbonate  of  copper. 

2  "  red  lead, 

Hyacinth. 

The  above  mixture,  with  the  addition  of  ten  grains  of  the 
oxide  of  manganese. 

Garnet. 

9  drachms  of  rock-crystal,  40  grains  of  saltpetre, 

8          "  dry  soda,  5        "         oxide  of  manganese, 

2          "  burnt  borax,  •  3        "  "         iron, 

li          "  red  lead,  1        "          cassius  purple. 

Rubellite,  Red  Tourmaline. 

1  ounce  of  rock-crystal,  1«  drachm  of  red  lead, 

1  "         dry  soda,  H          "        '   saltpetre, 

8  drachms  of  burnt  borax,  8  grains  of  oxide  of  nickel. 

Indigolite^  or  Blue  Tourmaline. 

The  above  mixture,  with  the  addition  of  the  carbonate 
of  cobalt. 

Chrysolite. 

6  drachms  of  rock-crystal,  1  drachm  red  lead, 

2  "  dry  soda,  10  grains  of  saltpetre, 

14         "  burnt  borax,  2       "         oxide  of  manganese. 

Amethyst. 

'  But  1  grain  of  the  oxide  of  manganese  to  each  ounce  of 
the  mass. 


IMITATIONS    OF   GEMS.  179 

Turquoise. 
In  the  above  mixture  use  instead  of  the  manganese — 

5  grains  of  dry  verdigris,  20  grains  of  bone-ashes. 

3        "         powder  blue, 

Lazulite. 

By  adding  to  former  mixtures^ 
2  grains  oxide  cobalt,  1  drachm  of  burnt  bone-ashef. 

Agate. 

By  mixing  together  several  frits  and  adding  oxide  of 
iron,  several  varieties  of  agate  are  obtained. 

It  will  now  be  necessary  to  show  the  distinguishing  char- 
acters between  the  real  and  artificial  gems,  as  they  so 
closely  resemble  each  other  that  a  superficial  inspection 
will  not  always  enable  the  examiner  to  discriminate  be- 
tween them ;  they  are  as  follows : 

1.  The  hardness  ;  which  may  be  tested  on  the  grinding 
machine  ;  with  fine  quartz  sand  it  will  immediately  attack 
the  pastes,  or  by  scratching  with  a  real  onyx,  to  which  the 
pastes  will  immediately  yield. 

2.  The  small  air-bubbles  in  the  pastes,  may  more  of  less 
be  detected  with  a  good  magnifying  glass. 

3.  The  cold  touch  will  never  remain  for  any  length  of 
time  on  the  pastes  as  it  will  on  the  real  gem. 

4.  The  breath  remains  much  longer  on  the  pastes,  on 
account  of  their  bad  conducting  power,  than  on  real  gems. 
The  specific  gravity  and  electricity,  may  likewise  indicate 
the  difference, — but  I  never  depended  on  them  alone,  and 
I  will  mention  that  I  once  examined  the  specific  gravity  of 
an  artificial  topaz  which  fully  corresponded  with  that  of  a 
Brazilian  topaz.     Electricity  will  indicate  the  difference 
between  real  and  artificial  gems  by  the  length  of  its  con- 


180  A  POPULAR  TREATISE  ON  GEMS. 

tinuance;  for  real  gems  retain,  after  being  rubbed,  their 
electricity  for  from  six  to  thirty-two  hours,  whereas,  the 
artificial  ones  only  retain  it  from  forty  to  sixty  minutes. 

_Z?.  The  Doublets.  This  mode  of  imitating  real  gems  is 
called  doubling,  when  a  quartz,  cut  and  polished,  is  ce- 
mented by  means  of  gum  mastic  to  another  colored  paste, 
whereby  the  whole  stone  assumes  the  color  of  the  lower 
paste.  When  a  real  gem'  is  employed  instead  of  quartz  (as 
the  surface  and  the  quartz  or  paste  is  cemented  below),  it  is 
called  half  doubling.  This  adulteration  is  carried  on  to  a 
very  great  extent  in  the  East  Indies,  where  they  paste  any 
thin  gem  to  a  paste  corresponding  in  color. 

The  concave  doubling  is  effected  by  excavating  the  inside 
of  a  quartz  or  paste.  The  cavity  being  filled  with  a  colored 
fluid,  and  the  other  part  afterwards  cemented  on  it,  will, 
when  well  executed,  present  so  uniform  a  color  that  it  is 
difficult  even  for  a  judge  to  detect  the  deception.  The 
surest  method  of  detection  is  to  put  the  specimen  in  ques- 
tion in  hot  water  or  alcohol,  by  which  the  gum  mastic  will 
be  dissolved.  When  set,  the  only  way  of  finding  out  the 
adulteration,  is  to  put  it  reversely  on  the  nail  of  the  thumb, 
when  the  false  refraction  of  light  or  the  rainbow  colors  will, 
with  certainty,  determine  its  identity. 

C.  The  Burning.  This  mode  of  adulterating  the  real 
gems,  is  performed  by  coloring  cut  and  polished  quartz 
specimens. and  throwing  them  into  a  solution  of  permanent 
pigments,  such  as  a  solution  of  indigo,  decoction  of  cochi- 
neal, solution  of  ammoniacal  copper ;  the  small  cavities 
produced  by  the  heat  will  absorb  the  fluids.  The  topaz  is 
burnt  by  itself,  with  or  without  the  absorption  of  a  pig- 
ment, as  also  the  spinelle,  and  the  quartz ;  chalcedony  is, 
however,  frequently  burnt  to  imitate  the  onyx,  and  to  en- 
grave thereon  cameos  and  intaglios. 

It  'may  be  remarked,  however,  that  since  the  introduc- 


GEMS   FOB   OPTICAL  PURPOSES.  181 

tion  of  colored  pastes,  very  few  adulterations  of  this  kind 
are  now  practised,  and  we  see  but  rarely  such  doublets  and 
burnt  stones. 

PRICE    OF   AJSD   TRADE   IN   GEMS. 

It  is  difficult  to  determine  the  price  of  gems  without 
reflecting  upon  all  the  circumstances  relating  to  them,  such 
as  beauty  and  uniformity,  the  play,  the  lustre,  and  the 
vivacity  of  the  colors,  and  also  on  the  perfection  of  the  cut, 
the  polish,  the  rare  locality,  the  size  of  the  individual  gems. 
It  depends  upon  the  trade  of  the  various  countries  whence 
they  come,  and  what  quantity  of  such  valuable  gems  may 
be  had  at  one  time  at  any  of  the  great  cities :  we  find  that 
diamonds  «re  often  sold  at  a  much  less  price  in  London 
and  Paris  than  in  Brazil.  The  principal  trade,  however, 
is  as  yet  carried  on  in  Brazil  and  the  East  Indies,  although 
it  is  in  no  comparison  so  prosperous  as  in  former  years. 
The  gems  are  sold  by  weight,  as  carat  and  grain-.  One 
carat  is  equal  to  four  grains,  and  forty-four  carats  are  equal 
to  one  ounce.  The  name  carat  is  derived  from  the  word 
kuara,  the  coral-tree  (erythrina),  the  red  pods  of  which", 
when  dry,  were  formerly  used  for  weighing  gold  dust,  and 
each  of  them  weighs  four  grains,  which  is  equal  to  one  carat. 

GEMS   FOR   OPTICAL   PURPOSES. 

A  few- years  ago,  Massrs.  Trecourt  and  Oberhauser  laid 
before  the  Parisian  Academy  lenses  of  the  diamond,, 
sapphire,  and  ruby,  which  were  used  in  connection  with 
glass  lenses  in  microscopes ;  they  were  of  nine-tenths  milli- 
metre, in  diameter.  The  diamond  lens  magnified  two 
hundred  and  ten  times,  that  of  sapphire,  two  hundred  and 
fifty-five  times,  and  that  of  ruby,  two  hundred  and  thirty- 
five  times,  in  linear  extension. 


182  A  POPULAR  TREATISE  ON  GEMS. 

A  letter  was  lately  published  from  Sir  David  Brewster, 
on  a  curious  optical  phenomenon  that  had  occurred  in  the 
construction  of  a  diagonal  lens.  The  diamond,  previous  to 
working,  had  all  the  appearance  of  internal  brilliancy ;  but, 
after  being  polished,  it  presented  a  series  of  stratified 
shades,  which  rendered  it  useless  for  the  required  purpose. 
It  afterwards  appeared  that  lapidaries  were  acquainted 
with  this  appearance,  which  rendered  them  extremely  un- 
willing to  take  the  risk  on  themselves,  of  cutting  up  dia- 
monds for  optical  purposes.  On  a  minute  examination  of 
this  phenomenon,  it  appeared  that  these  different  shades 
occurred  in  regular  strata,  each  section  being  about  the 
one-hundredth  part  of  an  inch,  and  each  stratum  having  a 
different  focus,  and  being  of  a  different  degree  %f  hardness 
and  specific  gravity.  The  inferences  drawn  from  the  above 
facts  were  : — that  the  diamond  was  a  vegetable  substance, 
and  that  its  parts  must  have  been  held  in  solution  and  sub- 
jected to  different  degrees  of  pressure  at  different  stages 
of  existence.  If,  on  the  contrary,  as  it  has  been  generally 
believed,  it  is  subject  to  the  laws  of  crystallization,  its  crys- 
tals must  necessarily  be  homogeneous. 


1  Stt.Beiyl.  2  Emerald.  3  Rube^e.  ^BrazaTopas.  5  Rulr/.  6  Star 
7  Opal.  8  Hyacinth.. 


PART  III. 


CONSIDERATION  OF  THE  INDIVIDUAL"  GEMS. 


DIAMOND. 

DIAMOND:  Diamant  (German),  Adamant  (of  the  an- 
cients), Almas  (Oriental),  Diamant  (French).  The  name 
Diamond  is  derived  from  the  Greek,  Adamas,  meaning  in- 
vincible, and  referring  to  the  hardness  of  the  gem.  The 
Syrians  are  said  to  have  first  known  the  diamond,  and  it 
was  in  early  ages  the  subject  of  trade  to  the  people  of  the 
East.  The  Carthaginians  are  said  to  have  carried  on  their 
trade  with  the  Etrurians,  who  procured  diamonds  from  the 
interior  of  Africa.  Pliny  mentions  six  species  of  diamonds, 
among  which,  however,  the  Indian  are  to  be  considered 
the  true,  in  contradistinction  to  the  quartz  crystals,  which 
were  likewise  called  diamonds  in  those  times.  The  dia- 
mond was  highly  esteemed,  and  many  medicinal  virtues 
were  attributed  to  it,  particularly  against  mania,  and  as  an 
antidote  for  poisons ;  it  was  worn  in  the  rough  state.  The 
art  of  cutting  it  with  its  own  powder  was  discovered  in  1476, 
by  Lewis  Van  Berghen.  In  the  beginning  it  was  cut  in  the 
table-form,  with  one  row  of  facets  on  the  surface ;  afterwards, 
in  1520,  the  rhomb  cut  was  adopted :  the  form  of  brilliants 
was  invented  in  the  reign  of  Louis  XII.  Cardinal  Mazarin 
was  the  first  who  had  diamonds  polished  in  this  form,  some 
of  which  yet  belong  to  the  crown  of  France.  For  a  long 


184  A  POPULAR  TREATISE  ON  GEMS. 

time  philosophers  vainly  speculated  as  to  the  nature  of  the 
diamond ;  first  it  was  considered  as  a  mineral,  consisting 
of  silica ;  but  Newton  was  the  earliest  (1675)  who  expressed 
himself  as  to  the  constitution  of  diamonds.  He  judged, 
from  the  great  refraction  of  light,  that  it  must  be  a  com- 
bustible body,  and  a  series  of  experiments  with  it,  tested 
afterwards  by  different  naturalists,  proved  the  same  to  be 
pure  carjbon.  The  first  trial  was  made  in  1694,  by  the 
members  of  the  Academy  at  Florence,  by  whom  diamonds 
were  volatilized  within  the  focus  of  a  mirror.  Bergman 
first  classified  the  diamond  among  combustible  bodies,  and 
mentions  having  cut  off  the  head  of  the  gems. 

Various  views  existed  in  regard  to  the  origin  of  the  dia- 
mond :  some  considered  it  as  a  secretion  of  a  vegetable 
substance ;  others  as  originating  from  volcanic  or  plutonic 
revolution.  The  Indians  believe  diamonds  are  continually 
regenerating  and  growing  to  this  date ;  and  the  inhabitants 
of  Pharrah,  in  Hindostan,  affirm  that  the  quantity  of  dia- 
monds by  no  means  decreases,  but  on  the  contrary,  the 
soil  will  yield  a  new  supply  fifteen  or  twenty  years  from 
the  time  it  is  exhausted. 

Numerous  experiments  have  been  instituted  to  produce 
an  artificial  diamond  from  several  substances  which  contain 
carbon,  and  by  the  application  of  a  high  degree  of  heat. 
The  late  Dr.  Hare,  in  Philadelphia,  succeeded  in  melting 
down  mahogany  charcoal  so  as  to  produce  a  metallic  ap- 
pearance, by  his  deflagrator.  Professor  Silliman  likewise 
made  similar  experiments  with  plumbago,  which  produced 
small  globules,  some  of  which  were  so  transparent  that  they 
could  not  be  distinguished  from  the  genuine  diamond. 
Professor  Yanuxem,  who  examined  the  globules  obtained 
from  fused  charcoal,  found  them  to  contain  iron  and  carbon, 
which  led  him  to  the  conclusion  that  the  charcoal  had  not 
undergone  a  real  fusion.  Cagniard  de  Latour  pretended 


DIAMOND.  185 

to  have  discovered  the  ingredients  for  imitating  diamonds 
of  some  size ;  but  Thenard  proved  those  small  crystals  of 
the  appearance  of  diamonds  to  be  some  silicates  of  pecu- 
liar composition,  which,  according  to  Arago,  polarized 
light  in  a  different  angle  from  that  of  diamonds.  All 
speculative  experiments  to  imitate  this  most  precious  gem 
by  the  various  compounds  of  carbon,  have  hitherto  proved 
abortive. 

The  diamond  is  found  crystallized  mostly  in  the  form  of 
an  octahedron  (composed  of  t\vo  four-sided  pyramids,  united 
by  their  bases),  or  rhombic  dodecahedron,  rarely  of  a  cube ; 
but  the  planes  of  the  angles,  are  often  rounded  or  bevelled. 
The  simple  octahedron  is  pretty  rare,  and  still  more  so  the 
cube ;  but  the  dodecahedron,  either  simple  or  complicated, 
is  very  frequent ;  the  crystals  are  sometimes  hemitrope. 
In  the  museum  of  tne  School  of  Mines  are  some  fine  macles, 
composed  of  two  crystals  crossing  each  other  at  right  an- 
gles. The  foliated  passages  are  distinctly  parallel  to  the 
faces  of  the  octahedron,  in  which  direction  they  may  always 
be  split.  The  fracture  is  conchoidal ;  surface  smooth,  often 
rough  or  striped,  and  sometimes  covered  with  a  scaly 
crust;  it  is  transparent,  also  semi-transparent;  of  an. ex- 
ceedingly vivid  lustre,  called  the  diamond  or  adamantine 
lustre,  and  when  polished,  of  splendid  fire  ;  it  is  limpid,  and 
likewise  passing  into  the  greatest  variety  of  shadings  from 
white  and  gray,  sometimes  from  yellow,  green,  and  brown. 

The  diamond  being  the  hardest 'of  all  substances,  yields 
to  no  file  ;  scratches  all  other  minerals,  and  is  not  touched 
by  any.  This  character  has  become  the  most  important  of 
the  diamond  since  the  late  discovery  of  the  amorphous  or 
compact  diamond.  It  is  very  frequently  tinged  light-green, 
but  more  rarely  with  orange,  red,  blue,  or  black ;  but'  in 
setting,  these  shades  disappear,  particularly  in  the  smaller 
diamonds ;  but  there  are  also  known  diamonds  of  rose  and 


186  A   POPULAR   TREATISE   ON   GEMS. 

pistachio-nut  green  colors.  The  blue  color  is  very  rare. 
The  blue  diamond  of  Mr.  Hope,  of  London,  is  one  of  ex- 
treme beauty  and  rarity,  and  is  of  immense  value;  the 
yellow  diamond  in  the  Museum  of  Natural  History,  in 
Paris,  is  likewise  very  remarkable  for  its  color  and  size. 
The  black  diamond,  which  is  perfectly  black,  although 
plainly  crystallized,  occurs  most  frequently  in  small  bristled 
balls,  but  crystalline  points ;  the  crystals  are  very  small, 
grouped  together  in  an  irregular  manner,  and  extremely 
refractory  to  the  cut ;  it  is  considered  the  hardest  of  all 
diamonds.  The  green  diamond  is  also  very  rare,  but  I 
have  seen  some  beautiful  specimens  in  the  Jardin  des 
Plantes  and  in  Freiberg,  the  first  in  the  cabinet  of  Abbe 
Hatty,  and  the  latter  in  the  cabinet  of  Werner.  Its  streak 
powder  is-  white  or  grayish  ;  it  becomes  phosphorescent  by 
the  rays  of  the  sun,  and  electric  by  rubbing,  which  property 
it  retains  for  half  an  hour;  its  specific  gravity  is  3'5-3'6  ; 
it  does  not  alter  before  the  blowpipe ;  it  burns,  however, 
at  a  high  degree  of  heat,  and  in  atmospheric  air  with  a 
bluish  flame ;  its  touch  is  very  cold ;  it  consists  of  carbon. 
The  diamond  bears  the  same  name  in  trade,  but  is  changed 
according  to  its  cut;  the  blackish  and  brownish  diamonds 
are  called  the  Savoy  diamonds  (Diamants  Savoyards).  The 
compact  and  amorphic  diamond  was  first  brought  to  notice 
by  the  experiments  of  Mr.  Dufrenoy,  about  five  years  ago, 
as  being  the  transition  from  the  crystallized  to  the  compact 
condition,  on  account  of  its  hardness  and  specific  gravity, 
and  has  become  a  great  article  of  commerce ;  it  cuts  glass, 
scratches  quartz  and  topaz,  has  a  specific  gravity  of  S^V— 
3'52,  and  is  completely  consumed  in  oxygen  gas;  it  occurs 
in  kidney-shaped  and  irregular  angular  masses,  but  not  in 
pebbles ;  the  exterior  is  generally  black,  sometimes  resem- 
bling the  graphite;  somewhat  resinous  lustre,  and  fre- 
quently its  form  is  very  singular,  the  outside  coating  being 


DIAMOND.  187 

black  and  resinous,  the  interior  forming  a  crystalline  ker. 
nel,  vitreous  and  lamellar,  like  the  diamond ;  it  is  reduced 
to  powder,  and  used  for  polishing  and  assisting  in  the  cut- 
ting of  the  diamond.  The  largest  specimen  of  the  compact 
diamond  weighs  about  46  carats,  and  belongs  to  Mr.  Hem- 
erdinger ;  and  a  compact  diamond  in  the  Museum  of  Natu-" 
ral  History  at  Paris,  weighing  about  seventeen  carats,  is 
•valued  at  fifteen  hundred  francs.  The  original  bed  of  the 
diamond  is  not  yet  known,  and  on  this  point  opinions  are 
much  divided.  In  the  East  Indies  we  find  it  in  a  conglom- 
erate of  sandstone,  consisting  of  quartz  grains,  and  disinte- 
grated by  the  ferruginous  sand ;  and  in  the  mountain  chain 
Ralla-Malla,  in  Hindostan,  between  95°  and  98°  E.  L. 
Some  of  the  celebrated  diamond  mines  consist  of  a  breccia 
from  argillaceous  slate,  quartz,  lime,  and  sandstone;  the 
boulders  and  the  sand  of  deserts  and  rivers  yield  diamonds 
mostly  rounded  or  in  a  granular  form.  The  richest  dia- 
mond mines  are  those  of  Roalcorda,  at  the  junction  of  the 
rivers  Bimah  and  Ristna;  Golconda,  along  the  shore  of 
the  Pennar,  Sumbhulpra,  and  Bundelkened,  in  the  neigh- 
borhood of  Pannah,  where  one  thousand  laborers  are  kept 
employed.  Visapur,  Hydrabad,  &c.,  on  the  island  of  Bor- 
neo, likewise  yield  diamonds ;  and,  according  to  Jameson, 
diamonds  were  found  in  the  Indies  in  the  coal  formation. 

In  Brazil,  they  were  discovered,  in  1728,  by  chance,  hav- 
ing been  always  thrown  aside  with  the  flint  and  other 
refuse  of  the  washings  of  gold,  until  an  inhabitant,  who  had 
some  knowledge  of  rough  diamonds,  collected  a  large  num- 
ber, and  carried  them  to  Portugal,  and  acquired  by  their 
sale  a  great  fortune.  Another,  who  was  informed  of  the 
operations  of  the  first,  shared  an  equally  good  fortune. 
The  government's  attention  was  drawn  to  the  matter,  and 
it  was  declared,  in  1730,  that  all  diamonds  found  there 
belonged  to  the  crown. 


188  A   POPULAK   TREATISE    OX    GEMS. 

Diamonds  are  found  in  the  talcose  chlorite  schist,  and  in 
a  breccia,  consisting  of  ferruginous  clay,  quartz  pebbles, 
sand,  and  oxide  of  iron  fragments ;  and  also  in  a  secondary 
bed,  accompanied  by  gold,  platina,  topaz,  beryl,  chryso-' 
beryl,  tourmaline,  kyanite,  amatose,  spinelle,  corundum, 
and  garnet.  They  are  found  particularly  in  the  valley  oi 
Sejues,  along  the  rivers  Jequetinhonha  and  Pardo,  which 
run  into  .the  diamond  district.  These  carry  most  diamonds 
by.  The  dykes  and  brooks  of  the  district  contain  more  or 
less  rich  diamonds,  which  are  found  there  in  recent  and 
older  beds.  Beyond  the  diamond  district,  the  diamond  is 
likewise  found  in  the  province  of  Minas  Geraes  on  the  Serro 
de  St.  Antonio,  in  the  Serro  Frio,  and  in  the  rivers  Aboite, 
Andaja,  da  Saneno,  da  Prata,  and  several  other  places, 
such  as  the  right  bank  of  the  Rio  San  Francisco,  and 
Matto  Grosso,  and  in  the  beds  of  Rio  Pardo  and  Rio  Vel- 
has ;  in  the  mines  of  Riven  and  Cuithe,  and  all  along  the 
valley  of  Peruguado  river,  in  the.  province  of  Bahia,  in 
some  of  the  tributaries  of  the  Rio  Doce,  on  the  banks  of 
the  Cachoine.  The  rocks  in  which  recently  diamonds 
have  been  found  consist  of  the  itacolumite,  a  micaceous 
sandstone,  accompanied  by  mrca-schist,  accidentally  trav- 
ersed by  quartz  veins.  This  is  the  prevailing  rock  in  the 
Serro  de  St.  Antonio,  in  which  the  Jequetinhonha  rises  in 
the  Serro  da  Matta  da  Corda,  on  the  eastern  slope  of 
which  the  tributaries  of  the  Rio  Francisco  rise  ;  and  in  the 
diamond  district  of  Tibagy,  very  rarely  in  the  alluvials  of 
ancient  rocks.  The  gold,  diamonds,  and  other  fine  stones, 
are  always  imbedded  in  the  lower  part  of  the  alluvium. 
Experience  -has  shown  the  richest  localities  to  be  in  Curran- 
linho,  Datas,  Mendanho,  Cavallo-Morte,  and  Caxoeira  de 
Inferno,  Avhere  the  alluvial  soil  is  from  eight  to  twenty 
feet  thick,  and  is  composed  almost  entirely  of  silicious 
sand,  strongly  colored  by  argillaceous  iron,  which  forms  a 


DIAMOND.  189 

species  of  cement  of  pebbles  of  quartz,  milky  quartz,  and 
itacolumite,  which  form  a  coarse  pudding-stone,  called 
casoelho,  and  which  is  considered  by  the  diamond- washers 
a  sure  sign  of  the  diamond.  Dr.  Cliffe,  the  proprietor  of  a 
diamond  mine  in  Brazil,  has  given  much  information  on 
this  subject. 

In  Russia,  the  first  diamond  was  discovered  in  July, 
18^9,  by  Humboldt  and  Rose,  when  on  their  journey  to 
Siberia,  on  the  west  side  of  the  Uralian  mountains,  in  the 
gold-washing  establishments  of  Krestowosdwisheaski,  be- 
longing to  Count  Schuwalow.  The  locality,  in  connection 
with  the  other  circumstances  of  the  place  where  the  dia- 
mond was  found,  bears  a  striking  resemblance  to  the  dia- 
mond district  of  Brazil.  The  predominating  rock  of  the 
spot  on  the  Uralian  mountains  is  a  quartzose  chlorite,  tal- 
cose  schist  (itacolumite),  with  an  admixture  of  iron  pyrites 
and  mica,  wherein  we  find  beds  of  red  oxide  of  iron,  talcose 
schist,  limestone,  and  dolomite.  In  the  valley  of  Poludenka 
and  Aedephskoi  the  diamonds  are  found  among  the  "debris 
of  the  mountains,  accompanied  by  quartz,  itacolumite, 
brown  hematite,  talcose  slate,  dolomite,  chalcedony,  ana- 
tase,  gold,  and  platina ;  it  is  not  yet  decided  to  what  for- 
mation this  rock  originally  belongs.  The  production  of 
diamonds  is  twofold;  either  they  are  dug  out  from  the 
earth,  or  they  are  collected  in  the  sand  of  rivers.  If  in 
the  latter  way,  they  are  more  or  less  rounded,  wedged, 
and  rubbed  off;  whereas  the  former  appear  coated  with  an 
earthy,  pale  gray,  yellow,  or  rose-red,  rarely  with  a  blue  or 
green  crust.  Many  valuable  mines  have  been  relinquished 
in  the  East  Indies  since  the  discovery  of  diamonds  in  Bra- 
zil. The  locality  of  the  finest  diamonds  is  at  present  in  the 
neighborhood  of  Sumbhulpore.  Two  tribes,  called  the 
Thata  and  Tora,  living  in  sixteen  villages,  occupy  them- 
selves particularly  with  searching  for  diamonds,  beginning 


190  A  POPDXAE   TEEATISE   ON   GEMS. 

in  the  month  of  November,  and  continuing  until  the  L 
mencement  of  the  rainy  season,  more  especially  in  the  bed 
of  the  Mahanudi  on  its  left  shore,  where  some  other  small 
rivers,  Maund,  Reloo,  Eeb,  &c.,  empty  into  it.  Four  or 
five  hundred  individuals,  consisting  of  men,  women,  and 
children,  are  examining  continually  all  the  spots  of  the 
river  from  Cauderpoor  to  Longpoor,  a  distance  of  about 
one  hundred  and  twenty  miles,  till  the  stream  is  imped'ed 
by  the  rocks  ;  and  likewise  all  excavations  or  other  cavities 
of  the  beds  where  any  alluvial  deposits  may  be  traced. 
All  their  implements  consist  of  a  pickaxe  (ankova),  a  board 
five  feet  in  length,  excavated  three  inches  in  the  middle, 
but  provided  with  its  border  (daer),  and  a  smaller  similar 
implement,  called  by  them  kootla,  both  of  the  shape  of  a 
shovel.  The  process  is  very  simple :  they  first  dig  the 
earth  with  the  axe,  and  let  it  accumulate  in  heaps. along 
the  shore;  the  women  afterwards  take  it  on  their  large 
shovels,  and  allow  the  water  to  run  over  the  earth ;  they 
then  pick  the  flints  and  coarse  gravel  out  of  it,  and  re- 
moving the  residue  on  smaller  shovels,  spread  it  out,  and 
examine  it  very  carefully,  separating  from  it  the  diamonds 
and  grains  of  gold.  Another  method  pursued  in  the  East 
Indies  is  to  surround  a  small  plain  where  the  diamonds  are 
expected  to  be  found,  with  a  wrall  two  feet  high,  under 
which  water  is  permitted  to  run  by -several  openings ;  after 
having  thrown  a  good  deal  of  earth  within  the  wall,  and 
having  allowed  the  water  to  pass  through  two  or  three 
times,  the  larger  stones  are  picked  out,  the  residue  dried, 
and  the  diamonds  selected  as  before. 

The  washing  establishments  of  the  diamond  in  Brazil, 
particularly  in  the  celebrated  district  Tejuco,  on  the  Rio 
San  Francisco  and  its  adjoining  smaller  rivers,  are  con- 
ducted in  the  following  manner : 

In  order  to  get  at  the  bottom,  or  soil  of  the  river,  means 


DIAMOND.  191 

are  used  for  leading  the  water  at  a  certain  spot  in  a  differ- 
ent direction,  and  then  that  part  of  the  bed  of  the  river  is 
allowed  to  dry  out,  and  the  sediment  consisting  of  a 
conglomerate  of  .quartz  pebbles,  kept  together  by  oxide  of 
iron,  is  brought  to  one  place  for  washing.  '  It  is  a  large 
bench  of  triangular  form,  so  as  to  keep  from  twenty  to 
thirty  negroes  busy:  in  the  middle  of  this  bench  is  a 
gutter,  with  which  is  connected  a  trough,  inclined  some- 
what, in  order  that  the  water  may  run  down  voluntarily, 
but  so  that  it  may  be  stopped  by  putting  loam  at  the  end  ; 
and  another  gutter  with  a  trough  is  joined  further  down. 
The  negro  who  has  collected  in  the  dry  season  a  large 
quantity,  of  the  sediment,  is  occupied  in  the  rainy  season 
in  putting  from  fifteen  to  eighteen  pounds  at  a  time  into  the 
trough,  spreading  it  there,  and  allowing  so  much  water  to 
run  over  it,  until  it  runs  off  quite  clear  from  the  lower 
trough,  but  at  the  same  time  keeping  the  trough  continu- 
ally moving.  He  then  begins  to  pick  out  the  larger  stones 
from  the  earthy  part,  and  afterwards  the  smaller,  until 
he  comes  to  grains,  which  he  examines  with  the  greatest 
care,  on  account  of  the  diamonds.  As  soon  as  a  negro 
has  found  one,  he  must  make  it  known  by  clapping  his 
hands,  and  the  surveyor,  who  is  seated  on  an  elevated 
chair,  so  that  f  he  can  oversee  the  work,  takes  and  de- 
posits it  in  a  dish  filled  with  water,  in  which  all  those 
found  during  the  day  are  collected.  They  are  then  de- 
livered over  to  the  superintendent,  who  counts  and  weighs 
them,  and  enters  the  result,  with  other  particulars,  in  a 
book  kept  for  that  purpose :  he  keeps  them  in  a  bag  until 
he  delivers  them,  which  he  does  twice  a  week,  to  the  gov- 
ernment at  Tejuco. 

Every  superintendent  has  to  live  in  the  neighborhood  of 
the  principal  washing-establishments,  which  were  formerly 
leased  for  a  certain  sum  by  the  government ;  but  the  im- 


192  A   POPULAR   TREATISE    ON    GEMS. 

positions  practised  were  so  great,  that  it  took  the  super- 
intendence upon  its  own  account  in  1722,  and  has  guarded 
the  diamond  districts  along  their  lines  by  strong  sentinels, 
who  will  not  allow  strangers  to  pass  through  .without  the 
permission  of  the  general  superintendent;  and  even  the 
inhabitants,  when  crossing  the  line  of  the  diamond  districts, 
have  to  procure  written  permissions  from  the  above  au- 
thority ;  and  everybody  must,  on  leaving  the  district, 
submit  to  a  personal  and  strict  examination  and  search  by 
the  soldiers ;  foot-passengers  are  always  arrested  by  sen- 
tinels and  spies  continually  on  the  alert.  St.  Antonio  de 
Tejuco,  forty  leagues  from  Villa  Rica,  is  the  capital  of  the 
diamond  district,  and  the  seat  of  the  superintendence  of 
the  Junta  Diamontina,  consisting  besides  of  a  confiskal, 
two  cashiers,  one  inspector-general,  and  a  book-keeper. 
Ail  the  diamonds  procured  are  delivered  up  yearly  to  the 
government  at  Rio  Janeiro. 

From  four  to  five  thousand  negroes  were  engaged  in  the 
years  1772  to  1775;  in  the  year  1818  but  one  thousand  : 
among  them  were  the  feitores  or  surveyors,  one  hundred 
in  number,  in  the  latter  year ;  likewise  ten  superintendents, 
whose  business  it  is  to  conduct  the  mining  department  and 
the  collection  of  the  diamonds. 

In  order  to  encourage  the  negroes,  presents  of  tobacco, 
cloth,  &c.,  are  awarded,  according  to  the  price  of  the  dia- 
monds which  they  find ;  the  one  who  finds,  for  instance,  an 
eighth  (seventeen  carats  and  two  grains)  receives  his  entire 
liberty ;  they  are  severely  punished  for  any  offence,  and  if 
repeated  are  not  allowed  to  be  at  this  work.  Notwithstand- 
ing the  most  rigorous  regulations  and  the  most  watchful 
attention  of  all  the  officers,  the  frauds  in  stolen  diamonds 
are  very  considerable  ;  and  it  is  estimated  that  the  smuggling 
amounts  to  one  third  of  the  whole  income*.  The  smugglers, 
who  are  runaway  slaves,  examine  the  most  remote  parts  of 


DIAMOND.  193 

the  district,  or  steal  the  diamonds  at  night  from  the  work- 
ing establishments ;  others,  again,  who  understand  it,  will 
take  the  stolen  diamonds  from  the  negroes,  and  devise 
means  of  escaping  with  them,  either  in  the  soles  of  their 
boots,  or  in  hollow  canes,  &c. ;  and  it  is  a  remarkable  feet, 
that  all  diamonds  obtained  from  the  smugglers  are  inva- 
riably larger  and  more  beautiful  than  those  which  axe 
brought  into  market  by  the  government.  The  thieves 
practise  all  manner  of  tricks  and  impositions,  even  in  the 
presence  of  the  surveyors :  for  instance,  they  conceal  the 
good  diamonds,  during  the  washing  hours,  between  the 
fingers,  the  toes,  in  the  ears,  in  the  mouth,  or  in  the  hair ; 
they  also  throw  them  away  with  other  stones,  in  order  to 
pick  them  up  in  the  night ;  they  often  even  swallow  them. 

The  soldier  who  arrests  any  smuggler,  receives  a  reward ; 
the  property  of  the  latter  is  confiscated,  and  he  is  sent  to 
Angola  as  a  prisoner,  for  upwards  of  ten  years. 

The  pure  transparent  diamond,  which  is  cut  in  the  differ- 
ent forms  already  mentioned,  loses  generally  one  third  to 
one  half  of  its  original  weight  by  this  operation. 

The  following  table  shows  the  original  weight  of  the 
rough  diamonds,  and  that  after  being  cut ;  viz, : 

Regent,  when  rough,  weighed  410  carats,  and  when  cut,  136u/ie  carats. 
Grand  Mogul,  "  "  7801/.,  "  "  279  »/i«  " 

Ko-M-noor,      "  "        ~186»/a          "  "  82"/16      " 

South  Star,      "  "         254'/a  "  "  124«/i«  .  " 

Nassak,  once  cut,  «  893/4          "  "  7810/i«     " 

It  will  be  perceived,  therefore,  that  the  skill  of  the  dia- 
mond-cutter has  made  great  progress  in  modern  times,  in- 
asmuch as  the  weight  of  the  Ko-hi-noor  and  South  Star 
was  only  reduced  to  one  half  of  the  original  weight. 

In  purchasing  rough  diamonds,  every  precaution  ought 
to  be  used  to  prevent  getting  false  diamonds  instead  of 

9 


194  A   POPULAR   TREATISE   ON   GEMS. 

real  ones,  and  faulty  ones  instead  of  pure  diamonds.  The 
officers  of  the  Junta  Diamontina  test  the  rough  stones  by 
holding  them  whilst  rubbing  together,  close  to  the  ear,  and 
listening  to  the  tone  produced,  which  gives  them  ample 
satisfaction  of  their  being  genuine,  as  it  is  only  to  be  ob- 
served in  real  diamonds.  It  requires,  however,  consider- 
able practice  to  distinguish  them  with  accuracy  by  this  test. 
Strangers  particularly,  are  imposed  upon  by  the  negroes 
in  Brazil,  by  purchasing  from  them  gems  cut  and  polished 
with  the  facets,  resembling  those  of  the  diamond;  and 
although  any  one  acquainted  with  the  diamond  will  soon 
detect  the  imposition  by  the  want  of  specific  weight,  the 
peculiar  lustre,  fire,  and  hardness,  he  requires  to  be  on  his 
guard.  If,  however,  the  diamond  is  ascertained  to  be 
genuine,  we  have  to  examine  particularly  its  purity,  color, 
form,  and  size,  these  being  the  qualities  by  which  the  price 
of  a  rough  diamond  is  to  be  determined. 

It  requires  considerable  experience  to  determine  from  a 
rough  diamond  whether  any  of  its  faults  are  at  the  surface 
or  in  the  interior,  whereby  often  the  diamond,  in  removing 
all  its  faults,  may  be  diminished  to  half  its  size.  We  often, 
however,  judge  the  rough  stones  by  their  color ;  those 
turning  towards  the  green  color  are  considered  to  be  the 
best ;  those  of  a  reddish  color  to  be  good  stones ;  the  black 
color  indicates  a  hard  stone ;  and  we  judge  a  yellowish  or 
grayish  color  as  making  bad  diamonds.  The  natural  form 
of  a  diamond,  likewise,  gives  a  characteristic  to  the  pur- 
chaser of  rough  stones ;  for  a  flat,  thin,  or  triangular  stone 
would  lose  much  in  the  grinding,  and  not  be  so  high  as  to 
give  it  sufficient  fire  ;  and  likewise  we  are  not  sure  of  the 
result  of  the  cutting,  and  the  hemitrope  crystals  are  very 
difficult  to  work.  The  best  forms  of  diamonds  for  cutting 
are  the  octahedron,  which  is  principally  found  in  the  East 
Indies,  and  is  called  Pint  by  the  diamond-grinders ;  and  the 


DIAMOND.  195 

rhombic  dodecahedron,  which  is  found  principally  in  Brazil : 
cheese-stones  is  the  name  given  to  amorphous  diamonds  b} 
the  diamond-grinders. 

According  to  the  quality  of  the  diamonds,  they  are 
divided  in  Sumbhulpur  into  four  classes,  which  correspond 
with  the  deities  of  the  Hindoos — the  Bramins,  Tschettri, 
Wassiers  (Bysh),  and  Tschadrie.  The  native  jewellers  are 
very  expert  in  estimating  the  value  of  these  diamonds. 

The  value  of  the  polished  diamonds  depends  on  the  fofc 
lowing  conditions : 

1st.  Color.  The  limpid  diamonds  command  the  high- 
est price,  and  twice  as  much  as  those  that  are  colored; 
the  blackish,  brownish,  yellowish,  brown,  steel-gray,  and 
impure  bluish  ones,  stand  in  no  value,  and  are  often  rejected 
for  working. 

2d.  Purity,  Faultlessness,  and  Transparency.  The  Dia- 
monds ought  to  be,  according  to  the  technical  terms  of 
the  jewellers,  free  from  ashes,  gray  spots,  rusty  or  knotty 
places,  veins,  fissures,  scratches,  feathers,  flaws,  sand,  grains, 
and  faint  yellow  or  vitreous  spots.  The  Brazilian  diamonds 
exhibit  sometimes,  in  their  interior,  designs  resembling 
mosses,  like  those  of  the  Mocha  stones  and  agates  ;  and  we 
may  often  observe  it  in  the  green  diamond ;  if  a  limpid 
diamond  plays  somewhat  in  the  brown*  color,  it  is  called 
shrugging,  and  this  diminishes  its  value :  paunched,  are 
those  diamonds  which  are  neither  pure  nor  clear. 

The  transparency  and  clearness  of  the  diamond  are  di- 
vided into  three  degrees,  viz : 

A,  of  the  first  water,  as  in  those  diamonds  which  are  free 
from  even  the  slightest  faults,  and  stand  highest  in  price. 

B,  of  the  second  water,  as  in  those  diamonds  which, 
although  clear  and  limpid,  are  marred  by  some  dark  spots, 
clouds,  or  flaws. 

C,  of  the  third  water,  as  in  those  diamonds  having  ?. 


196  A  POPULAR  TREATISE  ON  GEMS, 

t 

gray,'  brown,  yellow,  green,  Hue,  or  blackish  color ;  or 
those  that  are  limpid,  but  are  injured  by  several  material 
faults. 

In  order  to  determine  accurately  the  nature  of  diamonds, 
it  is  well  to  breathe  on  them,  whereby  they  lose  for  a  mo- 
ment their  lustre,  and  the  ,eye  is  then  better  enabled  to 
examine  them  and  distinguish  their  faults.  The  real  dia- 
mond becomes  clear  much  sooner  than  the  false. 
•  3d.  The  Cut.  The  perfect  and  regular  cut  of  the  dia- 
mond increases  its  value  considerably;  a  brilliant, -for  in- 
stance, of  one  carat,  is  worth  twice  as  much  as  a  rough 
diamond  of  equal  weight.  It  depends  upon  the  proportions 
of  the  height  to  the  circumference  of  the  diamond,  and 
that  the  planes  and  facets  stand  in  a  regular  proportion,  for 
should  this  not  be  the  case,  the  diamond  would  lose  much 
of  its  fire.  Likewise,  the  form  of  the  diamond  influences 
the  price.  A  brilliant  is  dearer  than  a  rose-diamond,  and 
this  again  is  dearer  than  the  thick  and  table-stone.  The 
facets  of  the  brilliant  also  influence  the  price  :  once  cut  is  a 
brilliant  that  possesses  no  cross-facets  on  the  lower  part  of 
the  stone ;  twice  cut,  there  is  one  row  of  facets  on  the  collet 
side;  thrice  cut,  the  brilliant  possesses  the  facets  on  the 
bizel  and  collet  side,  according  to  the  rule  of  cutting.  The 
more  rows  of  facets  a  brilliant  displays,  the  higher  price  is 
put  upon  it. 

4th.  The  Size  and  Weight.  The  price  of  a  diamond  de- 
pends considerably  upon-  its  size ;  those  diamonds  which 
are  of  great  splendor  and  size  are  called  Paragons'  or  Non- 
pareils, the  Ne  Plus  Ultra;  the  less  weighty  ones  are 
valued  according  to  their  actual  weight.  The  weight  em- 
ployed in  Sumbhulpur  is  the  rutta  and  masha.  Seven  rutts 
is  equal  to  one  mash,  and  one  rutt  is  equal  to  two  grains. 
In  Brazil  the  weight  is  specified  by  carats  (quilates). 
Seventeen  and  a  half  quilates  are  equal  to  one  drachm  (oc- 


DIAMOND.  197 

tava)  ;    thirty-two  vintenes  are  equal   to   seventy  grains 
(graos) ;  one  carat  is  equal  to  four  grains. 

The  price  of  diamonds  is  determined  in  trade  by  exam- 
ining accurately  their  character  as  above  stated,  and  then 
the  price  is  fixed ;  the  weight  of  the  diamond  is  at  first 
multiplied  by  itself,  and  the  sum  obtained  multiplied  again 
by  the  price  of  one  carat.  A  brilliant,  for  instance,  would 
weigh  two  carats,  and  on  examining  its  properties,  if  good, 
its  price  would  be  found  to  be  forty-four  francs.  We  pro- 
ceed in  the  following  manner  to  get  at  the  full  value  of  the 
diamond :  2X2X44  =  176  francs.  We  do  not  always,  how- 
ever, arrive  at  the  correct  result.  If  the  brilliants  are  very 
large,  and  exceed  the  weight  of  eight  or  ten  carats,  it  is 
difficult  to  arrive  at  a  standard.  I  will  endeavor  to  give 
below  a  table  of  the  prices  of  the  diamond  in  Holland, 
France,  England,  Germany,  and  .the  United  States,  as  far* 
as  ascertained,  and  as  near  to  the  actual  price  current  as  I 
could  obtain. 

Rough  diamonds  fit  for  cutting  are  worth  ten  or  twelve 
francs  per  carat ;  any  diamond  exceeding  the  weight  of  one 
carat  is  estimated  by  the  square  of  its  weight  multiplied 
by  eleven  or  twelve  francs  as  the  average  price. 


Eose-diamonds  of  first  water  and  one  carat, 
"                  second       "           « 

20  francs. 
18      " 
14     " 

Brilliants,  30  to  35  pieces  to*  the  carat,      -                * 
"         20         "            "            "            - 

U                JQ               U                    U                    U                    m 

«           5         "            "            "            - 
«           4          «            «            «            _ 

22      " 
40      " 
88      «« 
35      " 
36      " 

Brilliants  of  three  grains  are  in  much  demand,  and  are 
worth  fifty  francs  per  carat.  Those  of  three  carats,  used 
for  icentre-pieces  in  necklaces,  are  sometimes  worth  four 
hundred  francs.  Rose-diamonds  for  mounting,  and  forty 


198 


A  POPULAR  TREATISE  ON  GEMS. 


to  the  carat,  are  worth  twenty  francs  the  carat  ;  if  r*  little 
larger,  thirty-live  francs  per  carat. 

Diamonds  unfit  for  cutting,  and  used  by  glass-cutters  or 
glaziers,  are  worth  from  ten  to  fifteen  francs  per  carat,  and 
still  smaller  ones  are  worth  less  ;  they  are  now  employed 
by  lithographers  for  their  engravings  and  etchings. 

In  1837,  according  to  Ketot,  Pujoux,  and  Lucas,  the 
price  of  diamonds  of  the  first  water  was  three  hundred 
francs  per  carat  ;  and  second  water,  one  hundred  and  fifty, 


Diamonds  of  one  'grain  and  less, 
The  double  cut,  first  water, 

6  to  a  grain, 
Of  two  grains,       - 
Of  three  grains,    - 
Of  one  carat,         - 
A  diamond  of  6  grains, 


10 
12 
15 
18      '* 
of  6  carats, 


96  francs  per  carat. 
125       " 
150       " 
170      " 


-  200 
260-280( 

-  600 ' 

-  1000 

-  1400 

-  1800 

-  2400 

-  3500 

-  5000 


The  abqve  prices  are  from  Brard's  Mineralogie  appliquee 
aux  Arts.  •  .  '  « 

The  price  of  diamonds  (in  1855),  according  to  Mr. 
Achard,  a  celebrated  dealer  in  Paris  : 

Glass-cutters'  diamonds,  less  than  a  grain,  50  francs,  or  $10  00  per  carat. 
Diamonds  to  reduce  to  powder,        -        -  12      "  2-50        " 

These  are  the  natural  diamonds. 


Diamond  powder  for  polishing, 
Compact  diamond,  called  carbonite, 
"  in  powder, 

Diamonds  of  1  carat  are  worth    - 
"  2     "          " 


8  francs,  or  $1  75  per  carat. 
4-6        "  1  50        " 

6        "  1  '50        " 

250  francs,  or     $50  00 
800        "  160  00 

-  1,500        "  SOO'OO 

-  10,000         "  2000  00 


DIAMOND. 


199 


According  toBarbot,  the  present  (1858)  price  current  of 
diamonds  of  good  quality,  and  in  relation  to  their  weight 
and  various  forms,  is  the  following : 

A  diamond  of  1  carat  is  worth,  per  carat,  300  francs,  or  $60  00 


8  grains 


recut,  8  to  the  carat, 

<t      1g  U  (( 

not  recut,  8  to  the  carat, 
«        16          " 

«         20  " 


KOSES  FROM  HOLLAND. 

A  rose  of  1  carat  is  worth,  per  carat, 
"   3  grains    "     " 


A  rose  of  8  to  the  carat 
"      16        " 
"      50         " 
"    100         " 


240 
210 
180 
180 
190 
140 
150 
160 


48  00 
42  00 
36  00 
86  00 
38  00 
28  00 
80  00 
32  00 


200  francs,  or  $40  00 


170 
160 
140 
160 
165 
180 
200 


84  00 
32  00 
28  00 

32  00 

33  00 
36  00 
40  00 


If  2-500  stones  to  the  carat,  they  are  sold,  on  an  average, 
in  quantities,  at  one  franc  twenty  centimes,  or  twenty-five 
cents,  per  piece;  if  1000  to  the  carat,  twelve  and  a  half 
cents,  per  piece.  In  Antwerp  the  roses  are  sold  at  one 
hundred  francs  per  carat,  and  from  two  grains  upward 
they  are  sold,  when  mixed  in  quantities,  at  sixty  to  eighty 
francs  per  carat. 

In  the  United  States,  the  jjrice  of  diamonds,  in  1859,  de- 
pending on  their  perfection,  is  about  the  following : 

1  carat  stones,   -       -       -       -       *.       -    $85  to  $100  per  carat. 
3A        "  __-._.      70          80        " 

Melee  or  mixed  stones,  from  »/g  to  %  carat 
stones,   -------      50          60        " 

"Vt  carat  stones  the  same  as  the  melee. 

Va         "  from  $10  to  $15  more  than  the  melee  stones. 


200  A  POPULAR  TREATISE  ON  GEMS. 

A  good  white  and  perfect  diamond  of  two  carats 

weight  is  worth  from           -        -        -        -        -  f  300  to  $350 

A  3  carat  stone,       _______  500          600 

4  "                 -  900        1000 

5  "              •-_--__-  1000        1200 

Spread  diamonds,  meaning  flat  stones,  so  as  to  display  a 
large  surface,  whereby  the  collet  is  shorter  than  the  crown, 
are  generally  sold  much  cheaper ;  they  do  not,  however, 
display  tHeir  elements  with  the  brilliancy  of  a  diamond 
having  two  thirds  of  the  collet  and  one  third  of  the  crown 
in  size. 

At  a  most  extensive  sale  of  diamonds,  which  took  place 
in  the  summer  of  1837,  at  the  auction  of  Rundell  & 
Bridges,  London,  there  were  twenty-four  lots  put  up, 
which  produced  the  sum  of  forty-jive  thousand  eight 
Jmndred  and  eighteen  pounds,  nearly  two  hundred  and 
twenty-nine  thousand  dollars  !  Some  of  the  prices  were 
as  follows :  The  celebrated  Nassak  Diamond,  which  weighs 
three  hundred  and  fifty-seven  and  a  half  grains,  and  is  of 
the  purest  water,  was  purchased  for  thirty-six  thousand 
dollars.  It  is. considered  to  have  been  sold  at  a  price  con- 
siderably under  its  value.  A  magnificent  pair  of  brilliant 
ear-rings,  weighing  two  hundred  twenty-three  and  a  half 
grains,  formerly  the  property  of  Queen  Charlotte,  were 
bought  for  fifty-five  thousand  dollars,  a  price  infinitely  be- 
low their  usually  estimated  value.  A  sapphire,  seventy-five 
and  a  half  carats,  set  with  brilliants  for  a  brooch,  two  thou- 
sand four  hundred  and  sixtySve  dollars.  Brilliant  ear- 
rings, three  thousand  seven  hundred  and  fifty  dollars.  A 
brilliant  necklace,  four  thousand  three  hundred  dollars. 
Drop  emerald  ear-rings,  two  thousand  three  hundred  and 
twenty-five  dollars.  Brilliant  ear-rings,  four  thousand  two 
hundred  and  fifty  dollars.  A  Turkish  dagger,  mounted 
with  brilliants  and  rubies,  four  thousand  dollars.  A  single 


DIAMOND.  201 

brilliant,  eight  hundred  dollars.  A  brilliant  drop,  seventy- 
nine  and  a  half  grains,  five  thousand  nine  hundred  dollars. 
An  oblong  brilliant,  one  hundred  fifty-one  and  a  quarter 
grains,  fourteen  thousand  dollars.  A  brilliant  necklace, 
eight  thousand  dollars.  Brilliant  ear-rings,  twelve  thousand 
five  hundred  dollars.  Brilliant  necklace,  twelve  thousand 
five  hundred  dollars.  Brilliant  drops,  formerly  belonging 
to  Marie  Antoinette,  eight  thousand  eight  hundred  ancf 
seventy-five  dollars.  A  rose-diamond,  eight  thousand  five 
hundred  dollars.  A  brilliant  drop,  ten  thousand  five  hun- 
dred dollars.  A  round  brilliant,  seventeen  thousand  five 
hundred  dollars.  A  lozenge  brilliant,  three  thousand  five 
hundred  dollars,  &c. 

Frauds  in  diamonds  are  practised  by  dealers,  and  the 
purchaser  must  be  guarded.  The  white  spinelle  crystal- 
lizes also  in  regular  octahedrons,  but  is  not  as  hard,  and  is 
therefore  scratched  by  the  diamond.  The  angle  under 
which  the  light  is  polarized  in  either  of  the  other  gems  is 
very  different. 

On  comparison  with  the  prices  of  those  now  in  market, 
it  is  certain  they  have  much  declined,  which  is  partially  to 
be  attributed  to  the  immense  stock  which  has  been  brought 
from  their  native  locality.  According  to  Spix  and  Martius, 
there  have  been  produced  in  Brazil,  from  1772  to  1818, 
1,298,037  carats  of  diamonds — that  is,  in  the  time  of  the 
Royal  Administration;  but  that  during  the  Lease,  only 
1,700,000  carats  were  produced,  which  together  make 
2,998,037  carats,  or  1301-J-  pounds,  thus  averaging  from 
fourteen  to  fifteen  pounds  per  year ;  those  brought  into 
market  by  contraband  being  excepted.  The  value  of  the 
above  diamonds  (8000  reis  per  carat),  produce'd  in  Brazil, 
amounts  to  23,984,276,000  reis,  or  about  40,000,000  francs. 
This  sum  bears  no  comparison  to  the  expense  of  procuring 
them,  since  the  government  lately  paid1  forty  francs  fifty 


202  A   POPULAR   TREATISE   ON   GEMS. 

centimes  per  carat,  whereas  they  only  yielded  from  eight 
een  to  nineteen  francs.  On  this  account  the  administration 
at  Rio  de  Janeiro  has  been  induced  to  lease  the  mines  to 
private  individuals.  Owing  to  this  decrease  in  the  produc- 
tion, the  number  of  laborers  is  reduced.  The  richest  pro- 
duction was  in  1784,  when  56,145  carats  were  washed  out ; 
•and  the  poorest  in  1818,  when  they  procured  but  9396 
carats.  In  Brazil,  large  diamonds  are  much  rarer  than  in 
the  East  Indies,  where  they  are  in  general  of  much  better 
quality  than  in  Brazil.  In  the  latter  country,  from  1772  to 
1811,  they  found  but  thirty-six  diamonds  weighing  upward 
of  seventeen  carats,  and  from  1812  to  1818,  but  eighty- 
three  diamonds  weighing  over  eight  carats.  In  the  East 
Indies,  according  to  Breton,  from  the  year  1804  to  1818, 
there  were  found  in  Mahanues  twenty  large  diamonds,  the 
aggregate  weight  of  which  amounted  to  four  hundred  and 
thirty-six  carats  and  one  grain.  The  largest  was  found  in 
1809,  and  weighed  six  hundred  and  seventy-two  grains, 
but  was  of  the  third  water ;  another  of  three  hundred  and 
eight  grains,  and  another  of  two  hundred  and  eighty-eight 
grains. 

As  it  has  already  been  stated  that  the  artist  and  amateur 
have  to  be  on  their  guard  against  imposition  in  the  purchase 
of  diamonds,  it  may  be  well  to  state  that  there  is  the  one- 
half  brilliant,  having  the  form  of  a  brilliant  above  (the 
upper  pyramid),  but  no  lower  pyramid ;  or  another  stone 
is  pasted  on  by  means  of  mastic.  The  character  of  the 
stone  is  readily  detected  when  taken  out  of  the  mounting. 

Sapphires,  hyacinths,  emeralds,  and  topazes  are  some- 
times slightly  calcined  and  sold  for  diamonds.  The  first 
two  are  heavier  than  the  diamond;  they  are,  however, 
harder,  and  possess  more  fire. .  The  topaz  is  distinguished 
by  its  property  of  becoming  electric  when  heated,  which 
lasts  for  several  hours. 


DIAMOND.  •  203 

Rock-crystal  is  much  lighter,  but  brilliant  and  hard  ;  and 
the  same  character  is  applicable  to  the  strass. 

The  following  list  shows  the  size  and  weight  of  the  most 
interesting  diamonds  in  the  possession  of  different  sover- 
eigns. 

The  largest  diamond  is  in  the  possession  of  the  Grand 
Mogul,  and  according  to  Tavernier,  resembles  in  form  and 
size,  half  a  hen's  egg.  Its  weight  is  two  hundred  and 
n^ety-seven  and  three  sixteenths  carats.  It  was  found  in 
1552,  in  the  mine  'of  Colore,  a  short  distance  to  the  east  of 
Golconda,  and  is  valued  at  11,723,000  francs.  It  is  cut 
as  a  rose-diamond,  and  is  perfectly  limpid,  with  the  excep- 
tion of  a  small  flaw  at  the  end  o"f  the  girdle.  - 

The  diamond  in  the  possession  of  the  Rajah  "of  Mattan, 
in  Borneo,  weighs  three  hundred  and  sixty-seven  carats :  it 
was  found  on  that  island."  It  is  of  an  egg  form,  has 
a  cavity  towards  the  thinner  end,  and  is  of  the  first 
water. 

The  Orlow,  the  diamond  belonging  formerly  to  Nadir 
Shah,  sultan  of  Persia,  and  now  in  possession  of  the  Rus- 
sian crown,  weighs  one  hundred  ninety-four  and  three 
fourths  carats.  It  is  of  the  first  water,  without  flaws  or 
faults  of  any  kind.  Its  form  is  that  of  a  flattened  oval, 
about  the  size  of  a  pigeon's  egg — it  formed  the  eye  of  a 
Braminian  god — cut  in  a  pyramidal  form ;  it  is  one  inch 
three  lines  in  diameter,  and  ten  lines  high.  It  was  pur- 
chased by  the  Empress  Catharine  for  about  ninety  thousand 
pounds,  cash,  and  an  annuity  of  four  thousand  pounds,  but 
is  considered  of  more  value. 

The  diamond  in  the  treasury  of^llio  Janeiro,  was  found 
in  1771,  at  Rio  Abaite,  by  three  criminals,  who  delivered 
it  to  the  government,  for  which  they  were  pardoned.  It 
weighs  one  hundred  and  thirty-eight  and  a  half  carats. 

The  Austrian  crown  possesses  one  which  weighs  one  hun- 


204  m         A   POPULAR   TREATISE   ON   GEMS. 

dred  and  thirty-nine  and  a  half  carats,  and  is  valued  at  one 
hundred  and  nine  thousand  two  hundred  and  fifty  pounds. 
It  is  beautiful  and  well  formed,  but  its  color  turns  towards 
the  yellow. 

There  is  another  belonging  to  the  crown,  which  was 
formerly  in  the  possession  of  Charles  the  Bold,  of  Bur- 
gundy, who  lost  his  all  in  the  battle  of  Granson.  This 
diamond  was  at  that  time  the  largest  in  Europe.  A 
Swiss  soldier,  who  was  the  robber  thereof,  sold  it  foi^te 
crown  dollar  to  a  priest ;  and  after  passin-g  through  several 
hands,  it  was  purchased  by  Pope  Julian  II.  for  twenty 
thousand  ducats. 

The  Regent,  or  Pitt  diamond,  belonging  to  the  crown 
of  France,  is  said  to  have  been  found  in  Malacca,  and  was 
purchased  by  Mr.  Pitt,  then  governor  of  Bencoolen,  in 
Sumatra,  and  sold  by  him  to  the  Regent,  duke  of  Orleans, 
by  whom  it  was  placed  among  the  crown-jewels  of  France. 
It  weighs  one  hundred  and  thirty-six  and  three  quarters 
carats ;  is  cut  in  the  form  of  a  brilliant,  and  is  of  the  first 
water,  being  absolutely  faultless.  When  rough,  it  weighed 
four  hundred  and  ten  carats,  required  two  years'  labor  in 
cutting,  and  is  worth,  according  to  the  value  put  'by  the 
commission  of  jewellers,  in  1791,  twelve  millions  of  livres. 
It  was  much  admired  in  the  exhibition  of  Paris,  in  1855, 
among  the  crown-jewels  of  France.  . 

The  Sancy,  belonging  to  the  crown  of  France,  is  one  of 
the  celebrated  diamonds,  although  not  as  large  as  the  last 
mentioned,  still  a  very  beautiful  stone ;  it  is  of  a  pear-shape, 
is  cut  as  a  double  rose-diamond  of  an  oblong  figure,  and 
weighs  fifty-six  and  a  %lf  carats  (thirty-three  and  twelve 
sixteenths,  according  to  Barbot),  and  it  cost  600,000  livres, 
but  is  now  valued  at  double  that  sum. 

A  very  curious  history  is  attached  to  this  stone,  which 
may  not  be  uninteresting  to  the  reader,  for  its  peregrina- 


DIAMOND.  205 

tions  are  wonderful  and  are  well  worth  relating.  At  first 
it  was  seen  glistening  in  the  casket  of  Charles  the  Bold, 
the  last  duke  of  Burgundy,  who  lost  it  in  the  battle  of 
Granson ;  it  was  found  by  a  Swiss,  who  sold  it  to  a  priest 
for  two  francs,  he  resold  it  for  three  francs ;  it  is  then  lost 
eight  of  until  in  the  year  1589,  King  Anthony,  of  Portu-' 
gal,  pledged  the  same  among  other  stones  to  M.  de  Sancy, 
then  Treasurer  of  the  King  of  France,  who  retained  it  by 
paying  100,000  francs  for  it.  Henry  III.,  after  a  lapse  of 
time,  borrowed  it  for  the  purpose  of  pledging  it  to  the 
S \yiss  government,  but  the  servant  that  was  to*  convey  it 
to  that  country  disappeared,  and  was  not  heard  of  for  a 
long  time;  at  last  it  was  discovered  that  the  messenger 
was  assassinated  by  thieves  ;  but  the  faithful  servant  rather 
than  deliver  the  jewel  to  the  thieves  preferred  swallowing 
it.  .The  spot  where  the  body  was  interred  was  discovered ; 
being  disinterred,  on  dissecting  the  stomach  the  diamond 
was  found.  The  Baron  de  Sancy  disposed  of  it  to  James 
II.,  while  at  St.  Germains,  and  from  him  it  fell  into  the 
hands  of  Louis  XIV.  for  625,000  francs,  and  has  ever  since 
been  the  property  of  the* crown  of  France.  The  same 
stone  was  lost  in  1792,  with  the  greater  part  of  the  other 
jewels:  it  "was  founcj.  again  by  the  police  in  the  Champs- 
Elysees,  through  an  anonymous  letter. 

*The  Regent,  the  blue  diamond,  the  celebrated  onyx 
known  by  the  name  of  Abbe  Sugen's  communion-cup,  with 
other  diamonds  to  the  value  of  several  millions  of  francs, 
were  then  stolen,  and  but  few  of  them  recovered. 

The  blue  diamond  of  the  crown-jewels  of  France,  is  of 
a  rich  sky-blue  color,  and  weighs  sixty-seven  and  one  eighth 
carats;  it  was  valued  at  3,000,000  francs,  but  was  stolen 
among  the  other  jewels,  in  1792,  and  not  recovered.  It  is 
said,  however,  that  it  was  sold  in  1835,  by  an  agent  of  the 
Bourbon  family,  to  a  purveyor  of  the  Emperor  of  Russia, 


206          A  POPULAR  TREATISE  ON  GEMS. 

for  the  sum  of  500,000  silver  roubles ;  since  which  time  it 
has  been  in  the  hands  of  the  Princess  Paul  Demidoff. 

Russia  is  said  to  be  the  richest  country  for  diamonds; 
her  crowns  are  of  immense  value ;  that  of  Ivan  Alexiowitch 
contained  881  brilliants ;  that  of  Peter  the  Great,  847  ;  that 
of  Catharine,  2536,  and  the  present  emperor  has  purchased 
for  his  crown  an  immense  amount  of  brilliants. 

The  Shah-is  another  of  the  great  diamonds  belonging  to 
the  Russian  crown ;  it  is  an  irregular  prism,  of  fine  water, 
and  weighs  ninety-three  carats;  it  belonged  formerly  to 
the  Emperor  of  Persia,  and  then  to  Nadir-Shah,  "and  was 
stolen  by  the  revolting  soldiers. 

The  Polar  Star  belongs  to  the  Princess  Youssoupoff,  is 
cut  into  a  brilliant,  and  weighs  forty  carats. 

The  Prince  Esterhazy,  as  colonel  of  a  fine  regiment  in 
the  service  of  Austria,  Wears,  in  his  uniform  of  state,  a  tlia- 
mond  valued  at  twelve  millions  of  francs. 

The  Pacha  of  Egypt  has  a  diamond  cut  in  facets,  which 
weighs  forty  carats,  and  cost  700,00'0  francs. 

The  Piggot  weighs  eighty-two  and  a  half  carats ;  is  not 
very  fine  ;  was  sold  by  lottery,  in  1801,  for  750,000  francs, 
and  belonged,  in  1818,  to  the  jewellers  Rundell  &  Bridges. 

The  Nassak  belonged  formerly  to*  the  East  India  Com- 
pany; weighs  eighty-nine  and  three  quarters  carats;  has 
since  been  recut  by  order  of  the  Marquis  of  Westminster; 
weighs  at  present  but  seventy-eight  and  five  eighths  carats, 
and  is  valued  at  800,000  francs. 

The  Holland  Diamond  weighs  thirty-six  carats,  and  is 
valued  at  260,000  francs. 

The  Hope  Diamond,  which  weighs  forty-four  and  one 
eighth  carats,  is  of  a  beautiful  color  like*  sapphire ;  is  sus- 
pected of  being  the  same  stone  which  was  stolen  among  the 
French  jewels,  in  1792.  Owing  to  its  beauty  it  was  pur- 
chased for  450,000  francs,  but  is  worth  more.- 


DIAMOND.  207 

The  Dresden  Treasury  has  a  beautiful  green  diamond, 
like  emerald,  which  weighs  thirty-one  and  one  quarter 
carats. 

The  value  of  the  crown-jewels  of  France,  has  always 
been  29,000,000  franco;  among  them  are  comprised — 

Diamonds 16,730,203  francs. 

Pearls  (506  in  number) 996,700       " 

Colored  Stones— 

230Kubies , 

134  Sapphires 

-150  Emeralds... 


71  Topazes. 


3  Amethysts  (Oriental) 

8  Syrian  Garnets 

8  Other  fine  stones .- 

Mounted  jewelry 5,834,490 

Ornaments  and  trinkets 5,144,300 


360,604 


Total 29,066,487       " 

The  great  treasures  which  were,  stolen  on  the  17th  Sep- 
tember, 1792,  and  not  recovered,  contained  over  1000 
carats  of  IHlliants  and  roses  of  various  sizes  and  qualities. 
In  1810  the  Emperor  Napoleon  L,  after  purchasing  over 
the  Continent  all  the  diamonds  and  jewels  which  were 
formerly  stolen  from  the  treasury,  had  another  inventory 
made  out. 

A  very  black  diamond,  which  belonged  to  Mr.  Papst, 
who  sold  it  to  Louis  XV 111.  for  24,000  francs;  it  is  of 
dark-brown  color,  but  a  fine  lustre.  It  came  from  the 
collection  of  Dagni ;  but  it  is  not  known  what  has  become 
of  it. 

A  fine  rose-diamond  of  fifteen  carats,  in  the  possession 
of  Prince  Rioria,  at  Naples,  in  1830. 

Mr.  Halphen  owned  a  diamond,  in  1838,  of  twenty-two 
and  one  half  carats  weight,  of  a  magnificent  and  rare 
water. 


208  A   POPULAR   TREATISE   ON   GEMS. 

The  Nizam  belonging  to  the  King  of  Golconda,  is  a 
magnificent  rough  diamond ;  it  weighs  340  carats,  and  is 
valued  at  5,000,000  francs. 

There  are  two  rough  diamonds,  belonging  to  the  King 
of  Portugal,  one  of  which  weighs  215  carats;  they  were 
found  in  the  river  Abayte,  which  runs 'through  the  Province 
of  Minas  Geraes,  in  Brazil. 

A  magnificent  pyramidal  cut  diamond,  in  Brazil,  is 
valued  at  872,000  francs. 

A  rough  diamond,  found  in  the  river  Abatio  in  Brazil,  is 
in  the  possession  of  the  Prince  Regent  of  Portugal,  which 
weighs  an,  ounce  Troy. 

The  two  large  diamonds  belonging  to  the  Shah  of  Persia 
have  already  been  mentioned  in  the  first  part,  with  accom- 
panying figures. 

The  Turkish  crown  has  two  very  large  diamonds ;  one 
of  eighty-four  carats,  and  the  other  of  one  hundred  and 
forty-seven  carats.  The  latter  is  valued  at  eighty  thousand 
ducats. 

One  found  in  Brazil,  in  1780,  weighs  seventy-two  carats 
and  three  fourths  of  a  grain.  Another,  found  in  1803, 
weighs  seventy  carats.  They  are  both  at  Rio  Janeiro. 

The  largest  of  all  known  diamonds  is  said  to  be  in  the 
possession  of  the  King  of  Portugal.  It  was  found  in  Bra- 
zil, in  the  diamond  district,  and  is  as  yet  in  its  rough  state. 
It  is  of  the  size  of  a  chicken's  egg,  weighing  one  thousand 
six  hundred  and  eighty  carats  (above  eleven  ounces),  and 
is  estimated  in  value  at  fifty-seven  million  pounds  sterling. 
It  is  now  the  general  opinion  of  jewellers  and  mineralogists 
that  this  is  a  white  topaz. 

The  I£oli4-noor,  of  which  there  is  an  exact  representation 
on  the  frontispiece  of  this  work,  in  its  present  form,  belongs 
to  the  Queen  of  England;  it  is  translated  as  the  Mountain 
of  Light,  and  is  a  very  remarkable  gem,  both  for  its  size  as 


DIAMOXD.  209 

well  as  its  history.  It  belonged  formerly  to  the  Grand 
Mogul,  from  whom  it  passed  into  the  hands  of  the  sever-  ' 
eigns  of  Cabal.  Runjeet  Sing,  the  king  of  Lahore,  be- 
came possessed  of  it  in  1813,  after  a  victorious  war  against 
the  Shah  Shuja.  At  the  death  of  Runjeet  Sing,  t*he  East 
India  Company  took  possession  of  his  estates,  and  this  relic 
fell  into  their  hands,  and  by  the  latter  was  presented  to 
the  Queen  of  England.  Its  original  weight  was  one  hun- 
dred and  eighty-six  carats;  it  was  of  an  elongated  form, 
which  led  to  the  supposition  that  i^is  a  part  of  an  octahe- 
dral crystal ;  this  opinion  has  been  repeatedly  expressed, 
and  more  particularly  by  Mr.  Tennant,  who  believes  it  to 
be  a  fragment  of  the  Grand  Mogul's  diamond  described  by . 
Tavernier.  Its  awkward  shape  and  bad  polish  induced  the 
queen  to  have  it  recut,  which  was  done  by  Mr.  Gaword, 
who  gave  the  Koh-i-noor  the  form  of  the  Regent  Diamond, 
and  lost  thereby  nearly  one  third  of  its  original  weight. 
It  is  now  a  beautiful  diamond,  and  is  valued  at  two  millions 
of  pounds  sterling. 

The  Star  of  the  South,  a  Brazilian 'diamond,  found  in 
July,  1853,  is  at  the  present  day  the  largest  in  Europe, 
coming  from  Brazil.  It  belongs  to  Mr.  Halphen,  a  private 
gentleman,  and  weighs  two  hundred  fifty-four  and  a  half 
carats ;  as  a  crystal',  was  a  dodecahedron ;  it  has  a  specific 
gravity  of  3*529.  On  account  of  a  deep  cavity  of  an  octa- 
hedric  form,  by  which  it  appears  to  have  been  attached,  at 
a  previous  stage,  to  another  crystal,  it  is  ascertained  by  the 
French  lapidaries  that  "this  diamond  will  lose  nearly  half  its 
weight,  so  that  after  being  cut  and  faceted,  it  will  weigh 
about  one  hundred  and  twenty-five  carats,  but  will  still 
rank  as  a  princely  diamond.  It  was  found  by  a  negress 
employed  in  the  mines  of  Begagem,  one  of  the  diamond 
districts  in  the  province  of  Minas  Geraes. 

Another  large  Brazilian  diamond  was  found  in  the  river 


210  A   POPULAR  TREATISE    ON   GEMS. 

Abaite,  and  is  said  to  weigh  about  one  hundred  and  twenty 
carats. 

The  Nassdk  diamond  belongs  to  the  East  India  Com- 
pany, and  weighs  eighty-nine  carats.  A  beautiful  green 
diamond  is  shown  in  the  royal  collection  (griine  gewolbe), 
weighing  forty-eight  carats.  * 

Among  the  American  diamonds  may  be  mentioned  one 
in  the  possession  of  Capt.  Dewey,  having  been  found  in 
Virginia,  and  a  perfect  crystal — a  rhomboidal  dodecahe- 
dron, with  curved  faces,  of  greenish-white  color,  and  per- 
fectly transparent — weighing  about  twenty-five  carats.  It 
reflects  strongly  the  light,  and  has  a  brilliant  adamantine 
lustre.  Smaller  diamonds  have  been  found  in  Alabama, 
'three  of  which  belong  to  Mr.  Barnett  Phillips  of  Philadel- 
phia, weighing  one,»two,  and  three  carats  respectively,  and 
likewise  perfect  octahedrons.  In  Rutherford  County, 
North  Carolina,  a  'diamond  of  one  and  a  half  carats  was  in 
the  possession  of  Mr.  T.  G.  Glemson.  In  Hall  County, 
Georgia,  diamonds  have  been  found  several  times  ;  in  Cali- 
fornia some  diamonds  are  said  to  have  been  found. 

The  black  diamond,  which  has  lately  been  found  in 
Mexico,  in  the  Sierra  Madre,  is  also  attracting  the  atten- 
tion of  lapidaries,  being  harder  th#n  any  other  diamond. 

Description   of  the   Crown-Jewels  of  Queen  Victoria  Z, 
worn  at  Tier  Coronation,  28th  June,  1838. 

The  crown  in  which  her  majesty  "appeared  at  the  cere- 
mony of  the  coronation  was  made  by  Messrs.  Rundell  & 
Bridges.  It  is  exceedingly  costly  and  elegant";  the  design 
is  much  more  tasty  than  that  of  the  crown  of  George  IV. 
and  William  IV.,  which  has  been  broken  up.  The  old 
crown,  made  for  the  former  of  these  monarchs,  weighed 
upwards  of  seven  pounds,  and  was  much  too  large  for  the 


.      DIAMOND.  211 

head  of  he?  present  majesty.  The  new  crown  weighs  little 
more  than  three  pounds.  It  is  composed  of  hoops  of  silver, 
inclosing  a  cap  of  deep  purple,  or  rather  blue,  velvet ;  the 
hoops  are  completely  covered  with  precious  stones,  sur- 
mounted with  a  bah1,  covered  with  small  diamonds,  and 
having  a  Maltese  cross  of  brilliants  on  the  top  of  it. 

The  cross  has  in  its  centre  a  splendid  sapphire ;  the  rim 
of  the  crown  is  clustered  with  brilliants,  and  ornamented 
with  fleurs-de'-lis  and  Maltese  crosses  equally  rich.  In  the 
front  of  the  Maltese  cross  which  is  hi  front  of  the  crown  is 
the  enormous  heart-shaped*  ruby,  once  worn  by  the  chival- 
rous Edward  the  Black  Prince,  but  now  destined  to  adorn 
the  head  of  a  virgin  queen.  Beneath  this,  in  a  circular 
rim,  is  an  immense  oblong  sapphire.  There  are  many 
other  precious  gems,  emeralds,  rubies,  and  sapphires,  and 
saveral  small  clusters  of  drop  pearls.  The  lower  part  of 
the  crown  is  surrounded  with  ermine.  It  is,  upon  the 
whole,  a  most  dazzling  and  splendid  crown,  and  does  infi- 
nite credit  to  those  by  whom  it  has  been  designed  and  put 
together.  Her  majesty  has  expressed  herself  highly  pleased 
with  it. 

The  following  is  an  estimate  of  the  value  of  the 'jewels: 

20  diamonds  round  the  circle,  £1500  each ".....  £30,000 

2  large  centre  diamonds,  £2000  each 4,000 

54  smaller  diamonds  placed  at  the  angles  of  the  former. . .  100 

4  crosses,  each  composed  of  25  diamonds 12,000 

4  large  diamonds  on  the  top's  of  the  crosses 40,000 

18  diamonds  contained  in  the  fleur-de-lis 10,000 

18  smaller  diamonds  contained  in  the  same 2,000 

Pearlsr  diamonds,  &c.,  on  the  arches  and  crosses 10,000 

141  diamonds  on  the  mound 500 

26  diamonds  on  the  upper  cross .'....  3,000 

2  circles  of  pearls  about  the  rim 800 

£111,000 

The  following  list  of  jewelry  exhibited  at  the  London 


212  A   POPULAR  TREATISE   ON   GEMS. 

Industrial  Exhibition,  in  1851,  by  some  French*and  Eng- 
lish  manufacturers,  comprises  but  a  small  part  of  the  im- 
mensely valuable  treasures  therein  collected :  The  Queen 
of  Spain  allowed  the  manufacturer,  Mr.  G.  Lemonnier,  of 
Paris,  to  show  two  sets  of  her  jewels.  The  first  consisted 
of  a  diamond  necklace,  in  the  form  of  a  ribbon,  interlaced 
with  foliage  of  emeralds;  the  stomacher  and  shoulder 
knots,  from  which  were  suspended  very  large  emeralds, 
with  clusters  of  brilliants.  A  bouquet  was  formed  of  lilies 
of  brilliants,  the  leaves  of  emeralds,  and  ribbons  of  brilliants 
with  pendants  of  pearls.  The  ci'own  was  in  the  same  style, 
with  aiguillettes  in  the  form  of  flowers,  having  stamens  in 
pearls.  The  bracelet  was  likewise  a  ribbon  of  brilliants, 
•interlaced  with  emeralds.  Another  set  of  jewels,  made 
entirely  of  diamonds  and  sapphires ;  the  crown,  composed 
in  the  heraldic  style,  held  in  the  centre  of  diamond  flowers 
a  large  sapphire ;  and  a  stomacher  and  necklace,  with  a 
wreath  of  brilliants  and  sapphire  centres,  were  all  scrupu- 
lously matched,  and  attracted  the  attention  of  thousands  of 
spectators  while  the  exhibition  lasted. 

The  Russian  jewellers,  Messrs.  Jahn  &  Bolin,  of  St.  Pe- 
tersburgh,  exhibited  a  sparkling  diadem,  containing  11 
very  beautiful  opals,  67  rubies,  1811  brilliants,  and  1712 
roses.  A  bracelet  of  turquoises  and  diamonds,  and  a 
brooch  in  the  shape  of  a  knob,  composed  of  750  turquoises, 
with  a  pair  of  ear-rings  of  small  turquoises,  709  in  number. 

The  English  jewellers,  Messrs.  Hunt  and  Koskell,  ex- 
hibited such  a  profusion  of  gems,  valued  at  about  two  hun- 
dred and  fifty  thousand  pounds  sterling,  that  it  would  re- 
quire a  lengthy  description  to  give  but  a  faint  idea  of  them 
— from  the  rough  diamonds  of  all  sizes,  by  the  hundreds, 
to  the  most  exquisite  cut  and  polished  gems.  A  bouquet 
of  diamonds,  which  was  as  rich  as  it  was  elegant,  was  made 
so  as  to  be  entirely  taken  to  pieces,  even  to  the  petals  of 


DIAMOND.  213 

the  flowers,  for  the  purpose  of  cleaning,  and  for  forming 
into  seven  broaches.  They  had  some  particularly  beautiful 
bracelets :  one  in  emeralds  and  diamonds ;  another  in  opal 
and  emerald,  with  white  enamel. 

Messrs.  R.  &  S.  Garrard  &  Co.,  of  London,  made  a  sina- 
iiar  exhibition  of  gems  and  pearls,  with  a  profusion  of  bril- 
liants and  rubies,  which  would  occupy  a  lull  page  to 
describe. 

In  the  collection  of  Mr.  Herz,  in  London,  both  in  the 
London  Exhibition — exhibited  by  Mr.  Thistlethwayte — as 
well  as  in  his  private  residence,  I  examined  a  very  costly 
and  unique  collection  of  gems.  The  diamonds  he  possesses 
are  of  every  shade  and  color,  such  as  I  have  only  seen  in 
the  celebrated  Wernerian  cabinet  at  Freiberg,  and  Abbe 
Haiiy's,  at  the  Jardin  des  Plantes,  in  Paris,  where  they 
were  in  their  natural  state,  while  those  of  Mr.  Herz  are 
cut,  and  many  of  them  set.  He  had  a  bouquet  of  brilliants 
and  rubies,  valued  at  four  thousand  five  hundred  pounds 
sterling,  quite  magnificently  set ;  a  bracelet  of  splendid 
white  and  large  diamonds,  and  in  the  centre  a  yellow  bril- 
liant of  five  carats  weight, -which  he  valued  at  five  thousand 
pounds  sterling. 

Messrs.  Blogg  &  Martin,  the  diamond  brokers  of  Lon- 
don, kindly  opened  their  treasures  to  me,  and  my  eyes 
were  dazzled  by  three  bags,  weighing  about  five  pounds 
.each,  of  diamonds ;  most  of  them  cut  in  the  East  Indies,  and 
weighing  from  ten  to  tw'enty  carats  each.  They  were  not 
put  in  market,  but  kept  as  reserve,  and  the  value  of  that  lot 
could  not  have  been  less  than  half  a  million  pounds  sterling. 
I  beheld  many  unique  curiosities  in  hemitrope  crystals  and 
made  diamonds ;  many  thousand  carats  of  rough  crys- 
tals of  diamonds,  from  one  grain  to  twenty  carats,  all  as- 
sorted, in  packages,  besides  the  immense  valuable  supply  of 
perfect  rubies  of  ten  carats  and  upward.  The  scarcity  ot 


214  A  POPULAR   TREATISE   ON   GEMS. 

these  gems  in  general,  and  the  high  price  at  which  the  ru- 
bies were  tlien  sold  in  market,  formed  a  very  singular  con- 
trast while  viewing  so  large  a  stock  in  one  establishment. 
I  only  recollect  from  memory  what  I  saw  in  1851,  at 
Messrs.  Blogg  &  Martin's ;  the  sight  of  so  many  valuable 
gems  had,  however,  made  a  lasting  impression*  on  me. 

CORUNDUM. 

The  abo.ve  name  was  applied  to  a  different  species  from 
that  of  sapphire,  but  these  terms  are  now  generally  ac- 
knowledged to  be  synonymous ;  not  so,  however,  the  em- 
ery, which  does  not  belong  to  this  species. 

Both  occur  in  rhomboids ;  often,  too,  in  crystals  of  sec- 
ondary* form.  They  scratch  all  other  gems  except  the  dia- 
mond ;  their  streak  and  powder  are  white,  and  the  specific 
gravity  is  3*9-4 ;  they  acquire  electricity  by  rubbing,  which 
is  retained  for  several  hours ;  they  are  not  fusible  before 
the  blowpipe ;  with  difficulty,  by  means  of  borax,  they  form 
a  clear,  limpid  glass ;  acids  have  no  eifect  on  them  ;  their 
chemical  constituents  are  alumine,  silica,  and  oxide  of  iron. 

SAPPHIRE. 

This  name  is  derived  probably  from  the  Hebrew,  as  it  is 
often  mentioned  in  the  Bible.  It  is  not  certain  whether' 
the  ancients  were  acquainted  with  the  blue  variety  only 
of  this  gem,  and  were  ignorant  of  other  blue  stones,  such 
as  lazulite,  fluor  spar,  &c.  It  was  not  used  by  them  as  a 
gem,  probably  on  account  of  the  difficulty  of  working  it ; 
but  as  a  medicine,  many  peculiar  virtues  were  ascribed  to 
it.  This  species  has  hitherto  been  usually  divided  accord- 
ing to  its  different  colors.  The  name  of  ruby  has  reference 
to  a  red  color,  and  was  applied  by  the  ancients  to  the  car- 


SAPPHIRE.  .  215 

buncle.  Sapphire  oc<5urs  in  crystals,  in  rounded  grains, 
and  pebbles.  It  is  generally  transparent,  but  sometimes 
only  translucent,  or  displays  a  shine  of  light  of  six  rays,  re- 
sembling the  form  of  a  star.  It  possesses  double  refraction 
in  a  slight  degree,  and  a  vivid  vitreous  lustre,  which  some- 
times turns  to  that  of  mother  of  pearl.  Its  fracture  is  from 
conchoidal  to  uneven.  Its  principal  colors  are  blue  and 
red,  with  their  various  shadings ;  sometimes  white,  gray, 
yellow,  green,  brownish-green,  and  black. 

If  the  red  sapphire  (ruby)  is  exposed  to  a  great  heat,  it 
becomes  green,  but  when  cold,  returns  to  its  original  color ; 
the  green  sapphire  undergoes  no  changes. 

The  various  names  given  to  sapphire,  according  to  its 
color,  are — 

1st.  Ruby  (Oriental  ruby),  of  a  dark  crimson  red,  cochi- 
neal or  carmine,  and  rose-red,  mostly  inclining  to  violet- 
blue. 

a.  Oriental  hyacinth,  aurora-red. 

2d.  Oriental  amethyst,  palish  violet-blue ;  playing  some- 
times in  rose  and  purple  red,  like  the  common  amethyst, 
except  in  its  superior  lustre.  » 

3d.  White  sapphire,  limpid  and  perfectly  transparent; 
vivid  lustre,  resembling  the  diamond. 

4th.  Sapphire,  Oriental  sapphire,  from  the  darkest  to  the 
lightest  blue,  with  different  shadings,  whence  it  is  denom- 
inated by  different  terms,  such  as  male  sapphire,  of  a  per- 
fectly clear  Berlin  or  smalts  blue;  female  sapphire,  full 
blue,  with  a  tinge  of  white — sometimes  sky-blue,  with 
streaks  or  specks;  water  sapphire,  very  pale-blue,  and 
sometimes  discolored ;  cat  sapphire,  blackish  or  greenish 
blue,  often  not  transparent. 

5th.  Oriental  topaz ;  lightly  yellow,  lemon,  or  brownish 
straw  yellow,  sometimes  playing  into  green ;  it  is  distin- 
guished from  the  Qommon  or  true  topaz  by  color  and  lus- 


216  A  POPULAR  TREATISE  ON  GEMS. 

tre,  but  it  occurs  likewise  much  larger,  and  is  seldom  less 
free  from  faults  than  any  other  species  of  sapphire. 

6th.  Oriental  aquamarine;  greenish  blue,  pure  and 
transparent,  possessing  a  higher  lustre  and  greater  hard- 
ness than  the  common  aquamarine. 

7th.  Oriental  chrysolite,  or  peridote;  yellowish-green, 
resembling  in  color  the  chrysoberyl,  but  may  be  distin- 
guished from  it  by  its  higher  lustre. 

8th.  Oriental  emerald ;  green,  more  or  less  dark,  inclin- 
ing to  yellow ;  it  does  not  equal  in  color  the  real  emerald, 
but  possesses  a  higher  lustre,  and  is  at  the  same  time  very 
rare. 

The  sapphires  which  sometimes  display  a  peculiar  play 
of  light  are  divided  into — 

1st.  Star  sapphire  (asteria,  opalescent,  or  chatoyant  sap- 
phire). Some  translucent  sapphires  display,  if  held  before 
the  sun,  or  a  burning  taper,  a  white  light  running  in  six 
rays,  resembling  three  white  planes,  or  stripes  crossing 
themselves  at  one  point.  This  property  is  thus  visible 
when  the  sapphire  is  cut  convex  (or  caboehon),  and  when 
the  principal  axis  of  the  crystal  stands  perpendicular  to  the 
base  of  the  convex  cut  stone ;  these  star  sapphires  are  either 
called  ruby-asteria,  sapphire-asteria,  or  topaz-asteria,  ac- 
cordirfg  to  the  color  they  bear. 

2d.  Girasol  sapphire,  Oriental  girasol,  sunstone  sapphire, 
or  ruby  cat's-eye,  have  a  yellowish,  reddish,  or  bluish  shine, 
or  reflection  of  light,  generally  of  a  lighter  color  than  the 
stone  itself,  displayed  when  moved  or  turned  on  the  convex 
surface. 

Sapphire  is  composed  of  pure  alumina ;  the  opaque  con- 
tains about  one  per  cent,  oxide  of  iron  and  one  per  cent, 
silica ;  before  the  blowpipe  it  is  unaltered ;  fuses  with  bo- 
rax and  salt  of  phosphorus,  but  is  not  attacked  by  the 
strongest  mineral  acids ;  friction  excites  electricity,  and  in 


SAPPHIRE.  .217. 

the  polished  specimens  the  electrical  attraction  continues 
for  a  considerable  length  of  time.  The  perfect  and  color- 
less Fapphire  has  a  brilliant  lustre,  so  that  the  same  may  be 
confounded  with  the  diamond ;  its  hardness  is  inferior  to 
the  latter.  The  specific  gravity  of  the  blue  sapphire-  is 
3'9V9 ;  of  the  ruby,  3'909 ;  of  the  green  (Oriental  emerald), 
3-P49;  of  the  violet  (amethyst),  3'921. 

The  sapphire  was  well  known  to  the  ancients.  Pliny 
gave  a  description  of  the  star*  sapphire,  under  the  naine 
of  asteria,  The  sapphire  possesses  the  double  refraction 
in  an  indifferent  degree,  and  its  fracture  is  unequal  and 
conchoidal.  The  finest  ruby  sapphire  occurs  in  the  Ca- 
pelan  mountains,  near  Syrian,  a  city  of  Pegu,  in  the 
kingdom  of  Ava ;  also  in  the  sand  of  the  Expaillie  river, 
in  Auvergne.  Blue  sapphires  are  brought  from  Ceylon. 
Large  masses  of  blue  sapphire,  of  opaque  color,  have  been 
found  in  North  Carolina,  as  well  as  some  isolated  crystals 
in  Buncombe  County,  North  Carolina;  but  there  are  many 
more  localities  in  the  United  States,  such  as  New  Jersey, 
New  York,  and  Connecticut.  Sapphires  are  mostly  found 
in  the  sands  of  rivers,  or  in  boulders,  with  garnets,  zircons, 
kyanite,  and  in  basalt.  It  has  been  observed  that  the  blue 
sapphires  are  frequent  in  Ceylon,  but  not  the  rubies,  and 
that  in  Pegu  it  is  the  reverse.  The  most  celebrated  mines 
of  sapphire  are  at  Mo-gaot  and  Kyat-Pyan,  five  days'  jour- 
ney from  Ava.  The  Boa,  or -Emperor  of  the  Birmans,  re- 
tains all  the  larger  sapphires. 

For  cutting  a  sapphire  an  iron  mill  is  used,  and  for  pol- 
ishing, a  copper  mill,  or  one  made  of  alloy  of  lead  and  tin, 
to  which  a  horizontal  motion  is  given  by  ajrery  simple  ma- 
chinery ;  its  surface  is  charged  with  diamond  powder  and 
oil,  or  with  fine  emery  and  water.  A  thick  peg  or  gauge 
of  wood,  pierced  with  small  holes  in  all  directions,  is  set 
upright  on  the  lapidary's  bench,  close  to  the  mill.  The 

10 


218  A   POPULAR   TREATISE   ON   GEMS. 

.    !  0 

stone,  being  placed  on  the  surface  of  the  mill,  and  the  op- 
posite end  of  the  stick  to  which  it  is  cemented  being  in- 
serted  in  one  of  the  holes  of  the  gauge,  the  mill  is  put  in 
motion  by  turning  a  winch,  and  the  stone  kept  steady 
on  it. 

When  the  stone  has  all  the  facets,  the  cutting  mill  is 
taken  out  and  replaced  by  one  of  brass,  on  which  the  pol- 
ishing is  performed  by  means  of  fine  emery  and  rotten- 
stone,  in  the  same  manner  as  before.  A  good  judgment  is 
required  in  determining  the  form  and  proportions  best 
adapted  to  set  off  any  particular  stone  to  the  best  advan- 
tage. If  the  color  is  full  and  rich,  its  transparency  perfect, 
and  its  refractive  power  considerable,  the  best  form  to  give 
it  is  the  brilliant.  If,  on  the  contrary,  the  color  is  dilute, 
the  most  advantageous  method  of  cutting  it  is,  to  cut  the 
table  side  (pavilion)  brilliant  fashion,  and  the  collet  side 
(culasse)  in  steps ;  by  this  means  the  table  itself  will  be  left 
dark,  while  all  the  light  reflected  from  the  steps  on  the 
under  side  of  the  stone  will  be  thrown  up  into  the  facets, 
by  which  the  table  is  surrounded.  The  French  lapidaries 
cut  the  most  perfect  sapphires  in  a  square  or  octagon  form, 
with  a  single  delicate  -step  between  the  table  and  the 
girdle,  and  three  or  four  steps  between  the  girdle  and  the 
collet. 

If  the  sapphires  possess  a  varying  chatoyant  lustre,  or 
are  of  a  small  size,  their  form  is  always  hemispherical  or 
elliptical,  without  any  flat  facets;  the  flatter  the  ellipse 
the  more  the  varying  lustre  is  diffused  over  the  surface  of 
the  stone ;  whereas  with  a  high  ellipse  it  is  condensed  on  a 
single  spot. 

In  setting  samphires  we  always  use  foil  answering  to  their 
color.  The  ruby  is  set  with  a  reddish  gold  foil,  or  a  foil 
of  copper  or  red  glass ;  the  blue  sapphire  with  a  silver  foil, 
or  blue-colored  foil,  or  with  feathers  of  blue  ducks,  pigeons, 


SAPPHIRE.  219 

or  peacocks ;  and  the  water  sapphire  in  a  black  back  :  but 
all  perfectly  pure  sapphires  are  set  d  jour. 

Many  sapphires  may  be  deprived  of  their  specks  by  a 
careful  calcination  in  a  crucible  filled  with  ashes  or  clay, 
and  they  assume  then  a  more  agreeable  and  purer  color 
and  greater  transparency. 

Sapphires  are  very  favorite  gems,  and  are  extensively 
used  by  jewellers  for  setting  in  pins,  rings,  &c.  In  China, 
the  ladies'' slippers  are  mounted  with  rubies. 

The  blue  sapphires  have  'of  late  been  employed  as  lenses 
for  microscopes  with  great  success.  According  to  Brews- 
ter,  it  is,  for  its  refracting  power,  second  only  to  the  dia- 
mond, and  superior  to  all  other  gems.  A  new  use  has 
lately  been  made  of  the  sapphire  for  drawing  wires — it 
being  cut  in  the  form  of  a  wedge,  through  which,  by  means 
of  a  diamond-point,  a  circular  hole  is  drilled  and  then  fast- 
ened on  a  brass  plate;  the  wire  is  drawn  through  the 
smaller  aperture  of  the  sapphire  towards  the  wider,  by 
which  process  it  is  reduced  to  a  thinness  never  otherwise 
attained. 

The  price  of  sapphires  is  very  relative,  but  their  propor- 
tional value  is  next  to  that  of  the  diamond.  The  Oriental 
ruby  stands  highest  in  value,  and  when  perfect,  and  ex- 
ceeding three  carats,  is  generally  as  dear  as  a  diamond  of 
equal  weight  and  quality.  After  the  ruby,  blue  sapphire 
stands  next  in  value  ;  and  as  this  is  not  so  rare,  and  occurs 
in  large  specimens,  it  is  not  so  high  in  price.  Some  put 
the  price  of  the  blue  sapphire  equal  to  that  of  the  colored 
diamonds ;  others  put  the  price  at  half  that  of  a  brilliant 
under  similar  circumstances.  Sometimes  the  value  is  fixed 
by  multiplying  half  the  price  of  a  sapphire  weighing  a  carat, 
with  the  square  of  its  weight.  It  is  therefore  yery  difficult 
to  come  at  an  exact  price-current,  and  the  following  aver- 
age  prices  come  nearest  to  their  commercial  value : 


220  A   POPTJLAK  TREATISE    ON   GEMS. 


KUBY. 

Of  1  grain  weight : 2  francs. 

2  "          "       5      " 

3  "          "       12      " 

1  carat       "       20      " 

2  "  "  60  " 

3  »  "  '.  150  " 

4  "  "  250  " 

5  "  "  ..., '. 350  " 

BLUE  SAPPHIRE.  • 

1  carat 10  francs. 

2  "     20  " 

3  "     30  " 

4  «     45  " 

5  " 60  " 

6  " 80  " 

8  «     100  " 

10     " 200  " 

Smaller  stones  8  to  1  carat  are  worth. 8  " 

«         •     12tol.    "         " 6  " 

"    16  to  24  to  1       "         "         4  " 

In  order  to  show  the  various  prices  of  rubies,  we  cite 
the  sale  at  auction  of  the  Marquis  de  Dree's  collection,  at 
Paris 

For  a  cherry-red  Euby  of. 2    carats,  1000  francs. 

For  a  darker  Euby  of 11  "  400  u 

For  a  bluish-red  Euby 21  "  1400  ". 

For  a  lighter  Euby 3  "  1200  "     . 

For  a  blue  Sapphire 6  "  1760  " 

For  an  indigo-blue  Sapphire 6*  "  1500  " 

For  a  light-blue  Sapphire 4  "  123  " 

For  a  white  Sapphire 41  "  400  " 

For  an  Oriental  Amethyst 11  "  400  " 

For  a  fine  yellow  Topaz 61  ".  620  " 

For  a  lighter  Topaz 6*  "  71  " 

There  are  numerous  faults  and  defects  to  which  sapphiiv 
are  subject,  and  which  always  influence  their  price,  such  as 
clouds,  milky  or  semi-transparent  spocks,  like  chalcedony, 


SAPPHIRE.  221 

white  stripes,  fissures  or  knots,  &c.  The  sapphire,  partic- 
ularly the  red  and  blue  varieties,  being  great  favorites  in 
commerce,  are  often  imitated,  not  only  by  means  of  other 
colored  gems  resembling  them,  but  also  by  substituting 
pastes.  .Instead  of  ruby,  we  sometimes  get  the  spinelle, 
garnet,  hyacinth,  red  quartz,  calcined  amethyst,  red-burnt 
Brazilian  topaz,  red  tourmaline ;  and  instead  of  the  blue 
sapphire,  we  get  the  disthene,  kyanite,  and  the  cordier- 
ite, — hardness  is  the  best  test. 


NOTICE    OF    SOME    LARGE    SAPPHIRES. 

Tavernier  describes  two  large  rubies  said  to  have  be- 
longed to  the  King  of  Visapur,  one  of  which  weighed  fifty 
and  three  quarters  carats,  and  the  other  seventeen  and  a  half 
carats.  The  first  was  valued  at  sixty  thousand  francs, 
the  other  at  seventy-four  thousand  five  hundred  and  thirty 
francs. 

Th'e  prettiest  sapphire  at  present  in  the  Imperial  Museum 
of  France,  in  Paris,  is  without  fault  or  defect ;  it  weighs 
132T1g-  carats,  and  is  estimated  at  100,000  francs.  This 
sapphire  was  found  in  Bengal  by  a  poor  man  who  dealt  in 
wooden  spoons.  It  belonged  afterwards  to  the  mercantile 
house  of  Rospoli,  in  Rome,  who  sold  it  to  a  German  prince ; 
he  again  sold  it  to  the  jeweller  Ferret,  of  Paris,  for  1 70,000 
francs. 

Two  great  sapphires  belonging  to  Miss  Burnett  Coutts, 
of  London,  and  valued  at  750,000  francs,  were  much  ad- 
mired at  the  Paris  exhibition  in  1855. 

The  crown-jewels  of  France  contain  about  1 50  sapphires, 
of  an  aggregate  weight  of  350  carats,  and  are  valued  at 
600,000  francs. 

Several  sapphires  with  engravings  are  seen  in  Rome, 
such  as  Hercules ;  in  Turin,  in  the  collection  of  Genevasio, 


222  A  POPULAR  TREATISE  ON  GEMS. 

of  a  Tiberius'  head,  on  white  sapphire ;  in  St.  Petersburg, 
and  in  the  French  museum. 

Wahls  quotes  a  ruby  of  436  carats ;  and  Furetiere  saw  a 
ruby  in  Paris  of  240  carats ;  and  Tavernier  quotes  a  ruby 
of  half  the  size  of  an  egg,  with  the  engraving  of  Scheik 
Sephy. 

The  King  of  Aracan  possesses  a  crystal  of  blue  sapphire 
of  an  inch  in  diameter ;  and  Sir  Abram  Hume  possesses  a 
distinct  crystal  of  three  inches  in  length. 

The  star  sapphire  on  the  frontispiece,  was  formerly  in  the 
cabinet  of  Mr.  Gilmore  in  Baltimore. 

The  large  blue  sapphire  in  Hunt  &  Roskell's  case  at 
the  London  Exhibition,  was  extremely  beautiful,  and  the 
largest  I  ever  saw. 

The  ruby-sapphire  of  the  East  India  Company,  in  Lon- 
don, is  certainly  the  largest  in  the  world. 

In  the  collection  of  Messrs.  R.  &  S.  Garrard  &  Co.,  in 
the  London  Exhibition,  rubies  were  in  great  profusion — 
mostly  set  with  brilliants  and  pearls. 

The  price  of  rubies  depends  upon  fineness  and  color; 
they  are  sold  in  the  United  States  at  from  three  to  twenty 
dollars  per  carat. 

A  fine  ruby  is  worth  about  the  same  price  as  a  one  carat 
diamond  ;  and  a  two  carat  stone,  if  perfect,  is  worth  more 
than  a  two  carat  diamond. 

The  King  of  Pegu  and  the  monarchs  of  Siam  monopo- 
lize the  fine  rubies,  as  the  sovereigns  of  the  peninsula  of 
India  have  done  the  diamonds. 

The  finest  ruby  in  the  world  is  in  the  possession  of  the 
first ;  its  purity  has  passed  into  a  proverb,  and  its  worth, 
when  compared  with  gold,  is  inestimable. 

The  Subah  of  the  Deccan  is  also  in  possession  of  a  pro- 
digiously fine  one,  a  full  inch  in  diameter. 

The  Empress  Catharine,  of  Russia,  possessed  one  ruby 


CORUNDUM.  223 

of  the  size  of  a  pigeon's  egg,  presented  to  her  by  Gustave 
in.,  king  of  Sweden,  in  1777. 

Blue  sapphires  are  described  .by  the  English  embassy  to 
Ava,  of  the  weight  of  nine  hundred  and  fifty-one  carats. 
Mr.  Mawe  saw  a  blue  sapphire  of  three  hundred  and  ten 
carats.  In  the  crown-jewels  of  France,  there  is  one  rhom- 
boidal  crystal  of  one  hundred  and  sixty-six  carats. 

A  beautiful  ruby-asteria,  in  a  breastpin,  is  worn  by  Mr. 
W.  J.  Lane,  of  New  York. 


COMMON   COBUNDUM,   DIAMOND   SPAE. 

This  mineral  was  formerly  "brought  from  China  only, 
when  not  so  well  known  as  at  present,  and  bore  the  name 
of  common  corundum,  but  it  is  now  considered  as  belong- 
ing to  the  general  family  of  corundum.  It  occurs  in  crys- 
tals, which  are  generally  coated  with  some  crust ;  it  has  a 
conchoidal  fracture,  is  translucent,  and  has  a  lustre  between 
unctuous  and  mother  of  pearl,  either  gray,  red,  blue,  green, 
brown,  or  whitish  in  different  shadings.  It  is  mostly  in- 
closed in  granite,  mica  slate,  dolomite,  or  magnetic  iron, 
and  is  found  in  Piedmont,  Cananore,  Campo  Longo,  the 
East  Indies,  and  Sweden. 

All  the  corundums,  possessing  fine  and  pure  colors,  are 
used  and  cut  as  jewels,  and  the  impure  pieces  are  pulver- 
ized and  used  for  cutting  and  polishing  harder  stones,  or 
glass  .and  metals,  particularly  so  in  the  East  Indies  and 
China,  and  it  is  called,  in  Madras,  the  grinding-spar. 

It  may  be  remarked  that  the  Chinese  corundum,  which 
is  crystallized  in  prisms  of  six  sides,  bears  much  resem- 
blance to  the  emerald;  the  hardness  and  infusibility  of 
both  these  minerals,  and  their  geological  position  in  the 
middle  of  old  rocks  increases  their  similarity;  but  the 
emerald  cleaves  in  one  direction  parallel  to  its  base,  while 


224  A  POPULAR  TREATISE  ON  GEMS. 

the  corundum  cleaves  in  three  directions  of  its  f  rimitive 
angles;  the  emerald  has  a  less  specific  gravity,  as  three  to 
four ;  the  phosphate  of  lime  and  the  tourmaline  are  also 
found  in  six-sided  prisms;  but  in  all  these  cases  are  the 
cleavage,  hardness,  and  specific  gravity  the  distinguishing 
characters.  The  transparent  colorless  corundum  may  be 
confounded  with  the  diamond,  topaz,  aquamarine,  white 
spinelle,  and  quartz ;  in  these  cases  the  specific  gravity  is 
the  principal  distinguishing  character ;  the  white  corundum 
weighs  3*970,  the  diamond  3 '5 20,  aquamarine  2*7,  spinelle 
3'64,  the  topaz  3'4,  and  the  quartz  2'654. 

The  emery  or  granular  corundum  is  of  an  ash-gray, 
bluish-gray,  and  sometimog  brown  color ;  is  massive,  and 
opaque  or  slightly  translucent  on  the  edges  ;  -is  very  hard, 
and  scratches  easily  glass  and  quartz ;  is  found  in  a  bed  of 
talc,  in  mica  slate,  in  rounded  masses,  in  Naxos,  Italy,  and 
Spain,  and  in  great  abundance  on  the  summit  of  Gunnech- 
dagh,  near  Gumeschkeny,  about  twelve  miles  to  the  east 
of  Ephesus,  and  betwe'en  Eskihissar  and  Males,"  in  Asia 
Minor,  and  in  Ochsenkop,  near  Schwarzenberg,  in  Saxony. 
It  has  been  elaborately  described  by  Professor  J.  Law- 
rence Smith,  of  Louisville,  Ky.,  as  to  its  power  as  a  polish- 
ing material.  He  Jhas  ascertained  that  they  all  contain 
more  or  less  water,  and  that  their  specific  gravity  as  well 
as  their  hardness  depends  upon  the  percentage  of  water 
therein  contained ;  but  the  specific  gravity"  of  a  sapphire, 
ruby,  or  emerald,  which  contains  no  water,  is.4'06  to4'08, 
and  thatihey  generally  contain  from  1*60  to  3*90  per  ce'nt. 
of  water.  This  difference  does  not  result"  from  a  decom- 
position of  the  mineral  but  from  their  formation ;  he  proves 
that  the  presence  of  water  in  these  minerals  which  influ- 
ences their  hardness  or  specific  gravity,  was  existing  while 
they  were  on  the  point  of  crystallization,  and  his  experi- 
ments with  the  emery  from  China  and  Asia  Minor,  have 


CHRYSOBERYL. 


225 


led  him  to  a  scale  of  hardness  to  be  used  in  the  application 
of  emery  in  polishing  the  surfaces  of  certain  substances, 
— such  as  a  slab  of  stone,  or  a  plate  of 'glass,  or  any 
other  material  upon  which  emery  is  generally  applied  for 
polishing.  Professor  Smith's  process  consists  in  the  fol- 
lowing method:  he  reduces  the  emery  to  a  fine  powder 
in  a  steel  mortar,  similar  to  the  one  the  diamond-grinders 
use ;  the  powder  is  sifted  very  fine  through  a  sieve.  One 
gramme  of  this  fine  powder  he  employs  upon  a  glass  plate 
of  0*10  inch  diameter,  and  by  means  of  an  agate  pestle 
he  rubs  the  powder  circularly  and  rapidly,  until  the  pow- 
der meets  with  no  resistance  and  makes  no  scratching 
noise ;  the  quantity  of  glass-powder  which  is  hereby  taken 
up  by  the  emery  gives  the  index,  or  the  power,  of  the  em- 
ery under  trial. 


. 


CHRYSOBERYL,  CYMOPHAIfE. 

The  name  of  this  gem  is  derived  from  the  Greek,  and  is 
expressive  of  its  color ;  it  is  also  called  cymophane.  It 
was  formerly  classed  with  the  beryl  family,  but  was  sepa- 
rated from  that  by  Werner. 

It  occurs,  crystallized,  in  a  prismatic  form, 
also  in  boulders  and  grains ;  is  transparent 
to  translucent,  and  possesses  double  refrac- 
tion in  a  high  degree  ;  its  lustre  is  between 
unctuous  and  vitreous ;  exhibits  trichroism ; 
fracture  conchoidal;  its  color  asparagus 
and  olive  green,  with  a  tinge  of  brown, 
yellow,  gray,  or  white.  Some  specimens 
display,  sometimes,  a  milky  or  bluish-white 
lustre.  Chrysoberyl  scratches  topaz  and 
rock-crystal  very  distinctly,  but  is  attacked  by  sapphire ; 
the  streak-powder  is  white,  specific  gravity,  3*6S—  3'75 ; 

JO- 


Fig.  4. 


226          A  POPULAR  TEEATISE  ON  GEMS. 

hardness,  8*5.  It  becomes  electric  by  rubbing,  and  le- 
tains  this  property  for  several  hours  :  it  is  infusible  by  itself 
before  the  blowpipe,  but  is  slowly  fusible  into  a  glass  bead 
with  borax.  Its  component  parts  are  alumina,  silica,  and 
glucia,  with  some  oxide  of  iron  and  titanium.  In  com- 
merce, chrysoberyl  is  called  Oriental  chrysolite,  and  that 
displaying  lustre  is  called  opalescent  chrysolite.  Mr.  Ebel- 
man  has  produced,  artificially,  the  chrysoberyl  from  its  in- 
gredients. 

Chrysoberyl  is  mostly  found  in  loose  crystals  or  in. 
boulders  in  the  sand  of  rivers  associated  with  other  gems, 
such  as  spinelle,  sapphire,  topaz,  beryl,  &c.  In  Brazil, 
particularly  in  the  diamond  district,  and  more  frequently 
in  Termo  Minas  Novas,  Pegu,  Ceylon,  and  Siberia:  like- 
wise in  Connecticut  (at  Haddam),-  and  in  New  York  (at 
Saratoga),  imbedded  in  coarse  granular  granite,  and  ac- 
companied by  garnet  and  beryl. 

The  chrysoberyl  is  cut  on  a  brass  wheel  with  emery,  and 
polished  on  a  pewter  wheel  with  rotten-stone ;  it  is  very 
often  cut  in  cabochon  and,  if  perfectly  pure  and  transpar- 
ent, in  other  respects,  is  set  with  gold  foil,  and  used  for  rings 
and  pins. 

The  chrysoberyl  is  in  no  great  estimation,  on  account  of 
its  indifferent  fire  and  color,  but  those  specimens  that  take 
a  high  polish,  and  occur  transparent  and  pure  in  color,  and 
of  varying  lustre,  are  of  some  value ;  it  is  particularly  worn 
in  Brazil.  At  Paris  a  chrysoberyl  of  fine  green  color,  oval- 
cut,  seven  lines  in  length,  and  five  and  three  quarters  in 
breadth,  was  sold  for  six  hundred  francs ;  and  a  very  fine 
opalescent  chrysoberyl  nearly  five  lines  long  and  four  broad, 
cost  six  hundred  and  three  francs. 

For  chrysoberyl  have  been  substituted  apatite,  fluor  spar, 
and  pastes.;  but  it  is  harder  than  any  of  these  substances. 
Chrysolite  bears  a  great  resemblance  to  chrysoberyl  in  its 


SPIXELLE.  227 


external  appearance,  but  is  much  lighter  and  softer.  A 
green  chrysoberyl  was  found  in  Termo  Minas  Novas,  which 
weighed  sixteen  pounds,  the  largest  known.  It  is  in  the 
possession  of  the  government  at  Rio  de  Janeiro. 


SPINELLE. 

This  gem  was  called  by  the  ancients,  carbuncle.  It  only 
occurs  crystallized,  and  mostly  in  the  form  of  an  octahe- 
dron, and  its  modifications.  The  crystals  are  smooth, 
solitary,  or  grown  together  as  hemitropes,  loose,  o.ften 
rounded  like  grains  (figure  5  is 
a  made  form  of  the  spinelle  ruby)  ; 
its  fracture  is  conchoidal ;  it  is 
transparent  and  translucent ;  it 
possesses  simple  refraction  of  light ; 
is  of  a  highly  vitreous  lustre ;  and 
its  color  is  red,  turning  into  the 
greatest  variety  of  shadings  of 
blue,  brown,  and  yellow.  We 
find,  likewise,  blue,  black,  and 

green  spinelles,  which,  however,  have  no  commercial  value, 
on  account  of  their  impure  color  and  want  of  transpa- 
rency. 

Spinelle  scratches  quartz,  and  is  attacked  by  sapphire ; 
becomes  electric  by  rubbing;  its  specific  gravity =3*5 2 3, 
hardness = 7*56  ;  is  infusible  before  the  blowpipe.  Accord- 
ing to  Berzelius,  the  spinelle  of  Ceylon  when  heated,  grows 
first  brown,  then  black,  and  then  opaque,  which,  on  pooling, 
passes  into  green  and  limpid,  and  ultimately  into  its  origi-* 
nal  red.  Acids  do  not  affect  it ;  its  component  parts  are 
magnesia  and  alumina.  The  spinelle  is  classed  by  jewellers 
and  lapidaries  according  to  its  various  colors. 

1.  Ruby  spinelle,  or  spinelle  ruby;  of  a  light  or  dark 


228          A  POPULAR  TREATISE  ON  GEMS. 

red,  and  no  milky  lustre ;  shows,  if  held  near  the  eye,  a 
tinge  of  rose-red  color. 

2.  Ruby  balais,   or  balais  ruby;   pale-red  or  rose-red, 
sometimes  with  a  tinge  of  brown  or  violet. 

3.  Almandine  ruby ;  of  a  cochineal-red  color,  bordering 
on  blue,  violet-blue,  and  reddish-brown.     It  is  distinguished 
from  the  garnet,  likewise  called  the  almandine,  by  its  lighter 
color,  stronger  lustre,  and  greater  hardness. 

5.  Goutte  de  Sang  is  a  fine  cochineal  or  blood-red. spinelle. 

Spinelle  is  found  in  clay,  and  in  the  -sand  of  rivers,  with 
sapphire,  garnet,  tourmaline,  and  other  gems.  The  red 
variety  occurs  in  isolated  crystals  and  grains,  in  alluvial 
soil,  and  in  the  sand  of  rivers — Ceylon,  Ava,  and  Mysore — 
also  imbedded  in  gneiss  and  granite,  in  Ceylon ;  the  blue 
varieties  occur  imbedded  in  granular  limestone  at  Aker  in 
Sweden,  Rohleta  and  Lojusoken  in  Finland,  Straskau  Mo- 
ravia, in  the  dolomite  of  Nalande,  and  Candi  in  Ceylon ; 
the  white  variety  is  found  at  La  Ricia,  near  Rome,  with 
black  garnet  and  green  augite ;  the  grass-green  variety 
(chloi'ospinelle)  is  found  in  the  chlorite  slate  of  Slatoust,  in 
the  Ural.  The  black  and  brown  varieties  have  numerous 
localities ;  those  from  Orange  county,  New  York,  are  very 
large  and  perfect  octahedrons :  one  in  my  possession  was 
twelve  inches  in  diameter.  Spinelle  is  cut  on  an  iron  or 
brass  wheel,  with  emery  or  pulverized  diamond,  and  is 
polished  either  on  the  same  or  on  a  copper  wheel,  with  oil 
of  vitriol. 

Spinelle  is  cut  in  the  same  form  as  the  diamond,  and  is 
set  wit^  a  foil  of  copper  or  gold.  Its  color  is  often  .made 
%iore  intense,  and  its  faults,  such  as  flaws  and  specks,  re- 
moved, by  calcining  it  carefully. 

Lustre,  color,  and  hardness  have  made  the  spinelle  a 
very  favorite  gem,  which  is  used  in  a  great  variety  of 
ways,  as  in  rings,  pins,  necklaces,  &c. 


TOPAZ. .  229 

The  price  of  spinelles  it  is  difficult-  to  determine  with 
accuracy,  as  much  depends  on  their  properties ;  if  perfect 
and  exceeding  four  carats,  they  are  usually  worth  half  the 
price  of  diamonds  equally  large.  The  spinelle  ruby  and 
balais  ruby  are  the  most  esteemed  spinelles,  and  if  of 
twenty-four  to  thirty  carats,  are  worth  from  two  hundred 
to  four  hundred  francs ;  and  such  gems  are  often  sold  for 
true  rubies  (sapphire). 

Zircon  is  of  greater  specific  gravity  and  less  hardness 
than  the  spinelle,  and  shows  strong  and  double  refraction 
of  light.  Calcined  topaz  is  distinguished  by  its  electric 
properties.  Burnt  amethysts  are  lighter,  and  are  scratched 
by  spinelle.  Pastes  are  likewise  substituted  for  the  spinelle, 
such  as  glass  colored  with  gold-purple ;  but  as  the  spinelles 
are  always  harder  and  heavier,  the  adulterations  may  soon 
be  detected. 

According  to  Mr.  Ebelman,  the  artificial  spinelle  is  ob- 
tained by  the  following  mixture,  which  is  put  into  a  platina 
capsule  and  exposed  to  the  heat  of  a  porcelain  furnace : 
Alum,        -  6  grains. 

Magnesia,  3       " 

Fused  boracic  acid,    -  6       " 

Oxide  chrome,  O'lO  to  0*15. 

TOPAZ. 

It  is  not  determined  whether  the  ancients  meant  by 
topaz  the  same  gem  as  we  describe,  since  the  Greeks  un- 
derstood the  topaz  to  be  of  a  transparent  gold-yellow,  and 
the  Romans,  of  a  transparent  green-yellow.  The  name, 
which,  according  to  Pliny,  is  derived  from  Topazos,  an 
island  in  the  Red  Sea,  has  no  reference  to  its  color.  To- 
paz was,  in  former  times,  thought  to  possess  great  medicinal 
virtues;  for  example,  as  a  remedy  for  mania,  and  as  a 


230 


A  POPULAR  TREATISE  ON  GEMS. 


Fig.  6. 


strengthening  medicine.  The  topaz  occurs  crystallized  in 
a  rhombic  prism,  but  mostly  in  very  complicated  forms, 
particularly  the  Brazilian,  Siberian,  and 
Saxonian :  it  is  often  found  in  boulders. 
Its  fracture  is  conchoidal ;  it  is  transpa- 
rent and  translucent  ;  possesses  some 
double  refracting  powers ;  a  very  vivid 
vitreous  lustre  ;  clear,  straw,  sulphur, 
wine,  and  gold  yellow  colors,  sometimes 
with  a  tinge  of  violet-blue,  greenish,  and 
white.  Topaz  scratches  quartz  distinctly, 
but  is  attacked  by  sapphire.  Its  streak- 
powder  is  white ;  specific  gravity,  3*49  to 
3 '5 6 ;  it  is  phosphorescent  when  heated, 
with  a  bluish  or  yellowish  lustre,*  in  small  fragments.  It 
becomes  electric  either  by  rubbing,  heating,  or  by  pressure, 
and  retains  the  property  for  more  than  twenty-four  hours. 
Before  the  blowpipe,  at  a  strong  heat,  it  is  covered  with 
many  small  bubbles,  and  partly  loses  its  color.  It  is  dis- 
solved, fusing  slowly  with  borax,  into  a  white  bead  ;  acids 
have  no  effect  upon  it.  Its  component  parts  are  alumina, 
silica,  and  fluoric  acid. 

In  commerce,  topaz  is  distinguished  by  the  following 
names : 

1.  Water  clrops,  pebbles  (gouttes  d'eau),  clear,  limpid. 

2.  Siberian  topaz,  white,  with  a  bluish  tinge. 

3.  Brazilian  topaz,  gold-yellow,  with^a  touch  of  red. 

4.  Saxon  topaz,  pale  wine-yellow. 

5.  Indian  topaz,  saffron-yellow. 
6-.  Brazilian  ruby,  light  rose-red. 

7.  Brazilian  sapphire,  light-blue. 

8.  Aquamarine,  sea  and  mountain  green. 

Topaz  belongs  to  primitive  rocks,  and  is  found  in  chlorite 
slate,  gneiss  on  gangues,  argillaceous  schist,  <fec.     In  Bra- 


TOPAZ.  231 

zil,  it  is  found  in  a  decomposing  chlorite  slate  (and  is  there 
called  malacheta),  within  brown  hematite  cavities  or  quartz 
gangues,  which  are  of  one  inch  to  one  and  a  half  feet  thick, 
and  are  overlaid  by  indurated  talc  and  white  and  brown 
kaolin,  and  sometimes  intermixed  with  quartz  crystals 
and*  micaceous  iron,  which  are  the  surest  indications  of 
topaz.  Such  topaz  localities  are  at  Villa  Rica,  Capao,  and 
Lana.  Little  attention  is  paid  during  the  dry  season  to 
the  digging  of  topaz ;  but  with  the  beginning  of  the  rainy 
season,  the  searches  for  topaz  are  undertaken,  and  the 
operation  for  washing  and  procuring  them  is  performed 
like  that  of  the  diamond,  mentioned  under  its  proper 
head. 

In  places  where  the  topaz  is  found  in  company  with  tin 
ore,  it  is  picked  out ;  but  where  it  forms  a  part  of  the  rock, 
it  is  wrought  by  mining  operations,  as  in  Saxony. 

Topaz  is  cut  on  a  leaden  wheel,  either  with  emery  or  pul- 
verized topaz,  and  is  polished  on  a  copper  wheel  with  rotten- 
stone.  Care  has  to  be  taken  in  slitting  the  foliage.  The 
forms  which  it  is  to  receive  depend  upon  its  qualities  and 
purposes.  The  white  topaz  is  cut  in  brilliant  form,  with  a 
small  table  ;  the  bluish  topaz,  however,  is  cut  with  a  mixed 
form,  but  it  is  to  be  observed  that  the  table  side  requires 
to  be  higher  than  usual,  the. table  smaller,  and  the  collet 
side,  with  its  steps,  must  be  attentively  wrought  in  propor- 
tional distance.  The  yellow  topaz  is  mostly  cut  as  brilliant 
or  table-stone,  and  in  setting,  its  back  is  supplied  with  a 
gold  foil,  and  the  pale  with  a  red-colored  foil.  Many  spe- 
cies of  topaz  are  set  d  jour.  Topaz  assumes,  by  calcining, 
a  different  color,  and  also  by  coloring  fluids,  as  stated  in  a 
former  chapter.  % 

The  topaz  is  in  general  use  by  jewellers  for  setting  in 
lings,  pins,  ear-rings,  seals,  or  necklaces.  Its  fragments 
are  pulverized  and  used  for  grinding  the  softer  precious 


232          A  POPULAR  TREATISE  ON  GEMS. 

stones  ;  this  is  effected  by  calcining  them  first,  then  throw- 
ing them  into  water,  and  afterwards  pulverizing  them. 

By  heat  the  topaz  assumes  a  pink  or  red  hue,  so  nearly 
resembling  the  balais  ruby  that  it  can  only  be  distinguished 
by  the  facility  with  which  it  becomes  electric  by  friction. 

Topazes  from  New  South  Wales,  Brazil,  and  Scotland, 
sometimes  contain  cavities,  in  which  Sir  David  Brewster 
discovered  two  fluids,  one  of  which  has  an  index  of  refrac- 
tion=l*211,  and  expands  0*25  of  its  original  vo.lume  on 
being  heated,  from  10°  to  27°. 

The  topaz  is  found  green,  blue,  and  colorless  at  Ala- 
baschkka  Meersinsck,  Miask,  and  Adum  Tschelon  in  Sibe- 
ria ;  Kamtschatka,  Peru,  and  Rozena  in  Moravia,  with  lep- 
idolite ;  Mucla  in  Asia  Minor,  Peneg  in  Saxony,  and  at 
Schneckenstein,  near  Auerbach,  in  Saxony,  of  a  wine-yellow 
color;  at  Villa  Rica,  in  Brazil,  of  a  deep-yellow  color; 
with  tin  ore  at  Geyer,  Ehrenfriedersdorf,  and  Altenberg 
in  Saxony,  Schlackenwald  in  Bohemia;  with  tin  ore  and 
apatite  in  veins  of  granite  at  St.  Michael's  Mount  and  Huel- 
kirid,  near  St.  Agnes  in  Cornwall ;  in  granite  in  the  Morne 
mountains  in  Ireland ;  in  the  United  States,  at  Trumbull 
and  Middletown,  Connecticut. 

The  less  transparent  variety  (pyrophysalite),  with  fluor 
in  granite  veins,  at  Tinbo,  near  Fahlun,  in  S weden ;  in  bouX- 
ders  at  Braddbo,  in  Sweden ;  in  gneiss  at  Fossun,  in  Norway. 

Topaz  is  generally  of  less  value  now  than  formerly,  owing 
to  the  yearly  supplies  obtained  from  Brazil,  which  is  about 
forty  pounds.  The  mine  at  Capao  has  yielded  about  twelve 
thousand  dollars'  worth,  and  the  supply  has  been  accumu- 
lating at  Rio  de  Janeiro  and  Bahia  to  such  a  degree,  that 
it  is  disposed  of  at^  less  price  there  than  at  the  mines. 

Those  most  esteemed  are  the  rose-red  and  the  white,  or 
water  drops,  pingos  cFagoa.  A  topaz  of  the  size  of  a  bean 
is  sold  at  Chapada,  in  the  Termo  Minas  Novas,  at  one 


TOPAZ.  233 

dollar ;  one  of  one  carat  is  disposed  of  at  an  average  rate, 
for  eight  dollars;  a  yellow  one  for  three  dollars;  and  a 
yellow  burnt  one  for  five  dollars.  In  Brazil,  very  large, 
fine,  and  lustrous  ones,  bring  thirty  dollars.  * 

The  Saxonian  topazes  are  less  valued,  yet  good  yellow 
or  crimson  colored  ones,  nine  lines  long  and  seven  broad, 
bring  four  hundred  and  twenty  francs. 

Aquamarine  and  chrysolite  are  sometimes  substituted 
for  topaz;  but  it  may  easily  be  distinguished  from  them, 
not  only  by  its  hardness,  fracture,  and  specific  gravity,  but 
more  especially  by  its  property  of  becoming  electric  by 
rubbing.  This  will  prevent,  the  substitution  of  either  of 
the  above,  or  those  most  resembling  them;  such  as  the 
yellow  quartz,  chalcedony,  or  other  yellow-colored  stones. 

According  to  the  account  of  Tavernier,  the  Grand  Mogul 
possessed  an  octangular  polished  topaz  of  one  hundred  and 
fifty-seven  and  three  quarters  carats  weight,  which  has  been 
purchased  for  sixty  thousand  dollars. 

M.  d'Eshwege  notices-  a  topaz  crystal  ten  inches  in  length 
and  four  inches  in  diameter.  The  United  States  (Connect- 
icut) yield  topazes  of  an  opaque  color^  pale,  dark  orange, 
and  yellow,  twelve  inches  in  length.  One  of  the  finest 
Brazilian  topazes  I  have  seen  is  in  the  rare  collection  of 
Robert  Gilmore,  Esq.,  of  three  inches  length,  and  perfectly 
terminated.  The  Brazilian  topaz  on  the  frontispiece  was 
exhibited  in  the  London  Palace  by  Mr.  Tennant.  Some 
very  splendid  cut  Oriental  topazes  I  saw  at  *Mr.  Stephen 
H.  Palmer's;  they  were  of  wine-yellow  color  and  good  size. 

In  the  French  Imperial  Bibliotheque  there  are  several 
engraved  topazes — Philip  II.  and  Don  Carlos  in  white 
topaz,  and  engraved  by  Jacques  de  Trezzo  ;  and  in  a  very 
large  and  deq)  yellow  topaz,  an  Indian  Bacchus,  in  the 
Vatican.  The  House  of  Orleans  had  a  Mercury  seen  in 
profile,  on  ah  Oriental  topaz,  with  eight  facets. 


234  A   POPULAR   TREATISE    ON   GEMS. 

In  Turin,  in  the  Generosio  collection,  was  a  topaz  in- 
taglio, representing  Victory  in  a  chariot  drawn  by  two 
horses. 

Caire  possessed  an  Oriental  topaz  of  twenty-nine  carats, 
pierced  lengthwise,  with  the  following  words  in  Arabic  let- 
ters :  "God  only  will  accomplish."  It  was  an  amulet, 
known  by  the  Arabs  as  gri-gri. 

The  ancient  rona&v  was  found  on  an  island  in  the  Red 
Sea,  which  was  often  surrounded  with  fog,  and  therefore 
difficult  to  find ;  it  was  hence  named  roTra^a,  to  seek.  This 
name,  like  most  of  the  rnineralogical  terms  of  the  ancients, 
was  applied  to  seyeral  distinct  species!  Pliny  describes  a 
statue  of  Arsinoe,  the  wife  of  Ptolemy  Philadelphus,  four 
cubits  high,  which  was  made  of  ronafrv,  but  evidently  not 
the  topaz  of  the  present  day,  nor  chrysolite,  which  has 
been  supposed  to  be  the  ancient  topaz.  It  has  been  con- 
jectured that  it  was  a  jasper  or  agate  ;  others  have  imagined 
it  to  be  a  prase  or  chrysoprase. 

.  EUCLASE. 

Monoclinohedric  figures ;  cleavage  clinodiagonal,  highly 
perfect,  very  brittle  and  fragile ;  con- 
choidal  fracture ;  hardness,  7*5 ;  spe- 
cific gravity,  3* ;  transparent ;  splendid 
vitreous  pale  mountain-green,  passing 
into  yellow,  blue,  or  white.  When 
heated  befor^  the  blowpipe,  it  intu- 
mesces,  and  melts  in  thin  splinters  to  a 
white  enamel;  is  not  acted  upon  by 
acids;  is  composed  of  44'7  silica,  31*8 
alumina,  and  23'5  glucine,  with  1  to 
2-2  peroxide  of  iron,  and  0*4  to  0*7 
oxide  of  tin.  It  is  found  in  chlorite 
slate  at  Boa  Vista  'and  Capao,  near 


EMERALD.  235 

Villa  Rica,  in  Brazil ;  in  Peru,  and  is  said  to  have  been 
found  in  Siberia.  It  is  very  rare,  and  for  this  reason  not 
much  used  as  'a  gem ;  it  resembles  much  the  aquamarine 
when  cut. 

EMERALD. 

The  emerald  proper  and  the  beryl  belong  to  this  mineral 
species,  and  are  distinguished  by  their  color  and  crystalline 
form.  The  emerald  occurs  in  six-sided  prisms  with  their 
modifications;  it  scratches  quartz,  and  is  scratched  by 
topaz.  The  streak-powder  is  white ;  its  hardness  is  7*5  to 
8*0 ;  specific  gravity,  2'73  to  2'76 ;  it  becomes  electric  by 
rubbing ;  it  is  rounding  before  the  blowpipe,  and  forms  an 
opaque  black,  but  becomes  a  green  or  limpid  glass,  having 
the  hardness  of  borax.  Its  constituents  are  glucia,  alumina, 
and  silica. 

THE   EMERALD   PROPER. 

The  emerald  appears  to  have  been  known  in  the  most 
remote  ages,  and  was  the  third  stone,  according  to  Cal- 
met's  arrangement,  on  the  high  priest's  breastplate  of  judg- 
ment, with  the  name  of  Zebulon  inscribed  on  it.  In  the 
time  of  Pliny,  this  stone  was  held  in  such  high  estimation 
that  it  was  seldom  if  ever  engraved  upon.  The  moderns, 
however,  did  engrave  on  the  same,  as  we  find  in  the  royal 
collection  at  Paris  a  head  of  Henry  IV.,  and  one  of  Louis 
XIV.  It  has  been  excavated  from  the  ruins  of  Rome,  and 
from  Herculaneum  and  Pompeii.  But  the  ancients  often 
included  under  this  name  other  gems  of  the  same  color ; 
such  as  the  green  fluor,  aquamarine,  jasper,  malachite,  &c. 
They  appear  to  have'  obtained  the  emerald  from  Egypt. 
Cailloud  has  in  modern  times  succeeded  in  finding  the  old 
emerald  mines  in  the  Theban  deserts,'  on  the  Arabian  Gulf 
— which  have  been  noticed  by  the  ancient  authors,  and  by 


236  A   POPULAR   TREATISE    ON   GEMS. 

the  traditions  of  the  Arabs,  as  coming  from  the  mountains 
of  the  Sahara — when  sent  on  an  exploring  expedition  by 
the  Pasha  of  Egypt.  He  mentions  having  found  subterra- 
nean mines,  capable  of  allowing  four  hundred  men  to  work ; 
and  he  likewise  found  tools,  ropes,  lamps,  and  other  uten- 
sils. He,  judged  from  the  ruins  of  the  architecture  of  the 
temples  of  a  city  which  he  discovered,  that-  they  were  of 
Egyptian  or  Grecian  form,  and  about  one  thousand  years 
old. 

Among  the  church  treasures  of  the  ninth  and  tenth  centu- 
ries, we  find  the  emerald,  which  came  into  particular  notice 
after  the  conquest  of  Peru,  where  an  emerald  the  size  of 
an  ostrich  egg  is  said  to  have  been  idolatrized  by  the  savage 
inhabitants.  The'  emerald  was  formerly  used  as  medicine, 
and  was  worn  "as  a  preventive  against  epilepsy. 

The  emerald  occurs  in  somewhat  depressed 
six-sided  prisms ;  the  lateral  faces  of  which  are 
smooth ;  the  fracture  is  conchoidal  to  uneven ; 
it  is  transparent  to  translucent ;  displays  double 
refraction  in  a  slight  degree ;  has  a  vitreous 
lustre;  is  green  and  emerald-green  with  its 
different  shades. 

According  to  Mr.  Ebelman,  the  true  emerald  is  pre- 
pared artificially  by 

Silica    -  7*      grains. 

Alumina       -  1*60      " 

Glucia  -  1-40      " 

Fused  boracic  acid  -  4*06      " 

Oxide  chrome       -  O'lO      " 

It  is  scratched  by  an  English  file,  and  scratches  strongly 
white  glass,  and  slightly  quartz.  Its  specific  gravity  is  2*73 
to  2*77.  Its  color  is  owing  to  the  oxide  of  chrome.  An 
emerald  when  calcined,  and  thrown  into  water,  crumbles 


EMERALD.  237 

into  pieces  of  different  colors.  The  purest  emeralds  are 
called  the  Peruvian. 

The  emerald  is  found  in  micaceous  schist  at  Salzburg,  in 
the  Sahara  mountains,  in  gangues  in  Peru,  in  the  argilla- 
ceous and  in  hornblende  slate.  Formerly,  the  finest 
emeralds  came  from  Warta,  in  Peru;  but  the  mine  is 
either  exhausted,  or  the  Indians  filled  up  "the  mines  before 
they  left  them  at  the  conquest.  The  best  are  now  found 
in  the  valley  of  Tunca,  in  Santa  Fe,  where  they  occur  in 
granite.  The  emerald  has  lately  been  discovered  in  Siberia, 
in  the  micaceous  schist,  and  is  equal  to  the  Peruvian  in 
every  respect. 

The  emerald  is  sawed  into  pieces  with  emery,  cut  on  the 
copper  wheel,  and  polished  on  a.  finer  wheel  with  rotten- 
stone,  pumice-stone,  tin-ashes,  ancl  water.  .The  step-cut, 
and  the  mix^d  step-cut,  or  the  table-cut,  are  mostly  used, 
yet  it  is  sometimes  cut  as  a  brilliant  or  rose-cut.  They  are 
set  with  a  green  foil  or  green  satin  on  their  back ;  *or  some- 
times in  a  back  colored  with  mastic,  and  very  black ;  but 
if  perfectly  pure,  and  of  fine  color,  they  are  set  djour.  On 
exposure  to  air,  emeralds  grow  by  degrees  paler. 

The*  emerald  is,  on  account  of  its  agreeable  green  color, 
a  very  favorite  ornament,  and  is .  used'  for  the  most  expen- 
sive kinds  of  jewelry.  Its  value'  depends  altogether  ^upon 
its  pure  and  fine  color,  vivid  lustre,  and  the  size  of  the 
specimen.  The  price  of  emeralds  was  much  higher  before 
than  it  has  been  since  the  discovery  of  Mexico ;  the  prod- 
uct of  the  mines  of  Pern  reduced  their  price  considerably; 
now  they  are  getting  dearer  again,  and  always  command  a 
good  price.  A  small  box  of  fair  'emeralds  from  Peru, 
which  I  saw  a  few.  years  ago,  at  the  oifice  of  the  American 
and  Foreign  Agency,  in  this  city,  which  ^weighed  from 
three  to  four  pounds,  was  sold  afterwards  at  Paris  for  nine 
thousand  francs.  A  good  emerald,  of  fine  color,  is  worth 


238  A  POPULAR  TEEATISE   ON   GEMS. 

twelve  dollars  per  carat ;  and  the  price  increases  according 
to  its  intSrior.  qualities.  Jhe  price  of  the  best  emeralds  of 

4  grains  is  18  dollars. 

8       "  30       " 

16        "  ...  200       " 

24       "  .  ...  300       " 

48       "  '1000     '" 

Good  emeralds,  meaning  'good  color  and  quite  free  from 
flaws,  are  very  rare,  and  have  nearly  as  much  value  as  the 
ruby. 

An  emerald  of  twenty-four  grains,  and  good  color,  was 
sold  at  the  auction  of  the  Marquis  de  .Dree,  for  two  thou- 
sand four  hundred  francs.  Emeralds  of  indifferent  pale 
color,  are  sold  for  two  'dollars  per  carat.  The  faults  to 
which  emeralds  are  subject,  are  inequality  of  color  and 
transparency,  dark  or  white  spots,  fissur.es,  and  feathers. 
.  For  emeralds,  there  are  sometimes  substituted  the  green 
tourmaline. and  apatite;  the  former  is  easily  detected  by 
its  property  of  becoming  electric  by  heating  ;  but  in  gen- 
eral all  these  stones  do  not 'possess  the  lustre  and  hardness 
of  the  emerald.  The  pastes  in  imitation  of  the  emerald, 
are  so  well  manufactured  that  it  is  often  difficult  to  dis- 
criminate the  genuine  from  the  false.  The  following  yields 
the  best  imitation  of  the  emerald : 

1000  parts  of  discolored  strass, 

8      "          pure  oxide  of  copper, 
•02      "          oxide  of  chrome. 

An  emerald  is  said  to  have  been  at  the  Chapel  of  our 
Lady  at  Loretto,  in  Italy,  larger  than  a  man's  head,  and  for 
which  an  Englishman  offered  ninety  thousand  crowns. 

The  Sultan  of  Oude,  in  the  East  Indies,  is  said  to  have 
given  to  the  King  of  England,  among  other  presents,  an 
emerald  of  the  size  of  a  hen's  egg. 


EMERALD.  239 

The  treasury  of  Vienna  is  said  to  contain  an  emerald  of 
two  thousand,  two-  hundred  and  five  carats,  valued  at  three 
hundred  thousand  crowns. 

The  most  magnificent  specimen  of  emerald  was  presented 
to  the  cathedral  of  Loretto,  by  one  of  the  Spanish  kings. 
•It  consists  of  a  mass  of  white  quartz,  thickly  implanted 
with  emeralds,  more  than  an  inch  in  diameter. 

An  emerald  belonging  to  the  crown  of  Russia,  is  noticed 
in  the  Memoires  du  r&gne  de  Catherine,  Tmperatrice  de 
Ritssie,  as  being  of  the  size  of  a  hen's  egg.  .  ' 

A  fine  crystal  in  the  matrix,  is  in  the  museum  at  Dres- 
den, which  I  examined  in  1827. 

Among  the  large  emeralds  stands  foremost  the  magnifi- 
cent crystal  belonging  to  the  Duke  of  Devonshire,  as  repre- 
sented on  the  frontispiece  of  this  work;  it  is  a  regular 
six-sided  prism,  perfectly  well  formed  ;  two  of  the  parallel 
faces  are  more  developed  tha*h  the  others,  so  that  the 
hexagonal  base  of  the  crystal  has  one  side  larger  than 
the  rest ;  the  dimensions  of  the  base  are  2*36  inches,  by 
1'97  in  diameter,  and  it  weighs  eight  ounces  and  eighteen 
pennyweights ;  it  is  of  a  fine  green  color  and  perfectly 
clear  in  the  upper  part,  it  was  found  in  a  vein  of  dolomite, 
which  traverses  a  hornblende  rock  at  Muso,  near  Santa  Fe 
de  Bogota,  in  New  Grenada. 

A  prettier  but  smaller  specimen,  weighing  but  six  ounces, 
is  in  the  possession  of  Mr.  Hope,  of  London. 

Mount  Zalora,  hi  Upper  Egypt,  affords  a  less  distinct 
variety,  and  was  the  only  locality  which  was  known  to  the 
ancients. 

At  the  New  York  Exhibition,  in  1853,  quite  a  number 
of  emeralds  were  shown  from  the  New  Grenada  mine. 

Dr.  J.  R.  Chilton,  of  New  York,  has  a  very  beautiful 
crystal  of  emerald  in  the  matrix  in  his  private  cabinet,  of 
one  inch  in  length. 


240  A  POPULAR  TREATISE  ON  GEMS. 

The  largest  cut  emeralds  and  in  great  profusion,  set  in 
bridles,  saddles,  and  in  the  girdle  of  an-  apron,  about  the 
size  of  pigeons'  eggs,  were  in  the  East  India  Company's 
collection.  From  forty  to  fifty  of  that  size  were  set  to- 
gether, some  of  them  not  well  cut  and  polished,  but  all 
transparent  and  of  beautiful  green  color,  they  were  cer- 
tainly very  valuable. 

Mr.  Herz,  of  London,  has  a  beautiful  polished  emerald 
of  112  carats.' 

Mr.  Stephen  H.  Palmer,  jeweller  of  this  city,  has  some 
very  fine  cut  emeralds,  one  of  which  weighs  four  and  seven 
eighths  carats,  for  which  he  asks  $350. 

The  prettiest  cut  emerald  is  in  the  imperial  cabinet  of 
St.  Petersburg ;  it  weighs  thirty  carats ;  is  of  pure  color, 
and  a  perfect  stone ;  it  has  a  round  form  with  too  many 
facets. 

The  emerald  has  been*  very  successfully  imitated,  so 
much  so  that  the  most  experienced  eye  may  sometimes  be 
deceived. 

BERYL,  AQUAMARINE. 

This  gem  was  likewise  known  to  the  ancients,  who  con- 
sidered and  described  it  as  a  sea-green  precious  stone,  and 
called  the  yellow  varieties  of  this  mineral  the  chrysoberyl. 
It  was  used'  by  the  Romans  as  ornaments  for  cups,  also  for 
cameos.  The  crystals  of  the  beryl  are  six-sided,  terminated 
by  six-sided  pyramids,  they  also  taper  gradually  from  one 
end  to  the  other ;  the  lateral  faces  are  striated ;  the  frac- 
ture is  conchoidal  or  uneven ;  they  are  transparent  or  trans- 
lucent at  the  angles,  with  indistinct  double  refraction,  and 
vitreous  lustre  :  the  colors  are  green,  bluish-green,  yellow- 
ish-green, or  greenish-white  ;  bluish,  sky,  smalts,  or  indigo 
blue ;  straw,  wax,  or  honey  yellow ;  all  pale  colors :  hard- 
ness,?^ ;  specific  gravity,  2'67  to  2:71.  According  to  its 


BERYL.  241 

color  and  transparency,  it  is  designated  the  common  and 
precious  beryl :  under  the  first  are  generally  comprised  the 
greenish  and  blue  varieties,  which  are  also  called  the  aqua- 
marine ; '  whereas  the  yellowish  varieties  are  exclusively 
called  the  beryl,  and  are  generally  divided  thus  : 

1.  Aquamarine,  pure  pale  sky-blue.  .    »  , 

2.  Siberian  aquamarine,  pale  greenish-yellow,  of  a  vivid 
lustre,  faigt  color. 

3.  Aquamarine  chrysolite,  greenish-yellow,  and  yellowish- 
green,  vivid  lustre. 

The  beryl  belongs  to  the  primitive  formation,  is  found 
in  quartz  veins  and  granite  (graphic  granite),  and  is  associ- 
ated with  garnets,  quartz,  chrysoberyl,  schorl,  topaz,  &c. 
The  most  magnificent  beryls  come  from  Siberia,  Rio  de 
Janeiro  in  Brazil,  Aberdeenshire  in  Scotland,  and  Limoges 
in  France.  The  common  and  translucent  beryl  occurs  all 
over  the  globe,  and  in  the  United  States  in  great  abund- 
ance, where  it  is  without  mercantile  value.  The  granite 
rocks  of  New  Hampshire  (at  Acworth),  have  brought 
forth  gigantic  beryls,  perfect  six-sided  crystals,  three  fee,t 
in  length  and  four  feet  in  circumference,  and  weighing  up- 
wards of  three  hundred  pounds,  and  some  with  a  distinct 
termination  of  the  crystals.  Specimens  of  this  description 
may  be  seen  in  the  collection  of  the  Lyceum  of  Natural 
History,  New  York,  in  Mr.  Gilmore's  collection  at  Balti- 
more, and  in  the  author's  collection.  Large  quantities  of 
beryl  crystals  have  also  been  found  in  Chester  county, 
Pennsylvania. 

The  beryl  is  cut  on  a  leaden  plate  with  emery,  and 
polished  with  rotten-stone  on  a  tin  plate,  and  generally  of 
the  brilliant  cut,  on  account  of  Its  not  possessing  much 
lustre  in  the  interior. 

The  foil  that  is  required  in  mounting,  depends  upon  the 
color  of  the  stone :  the  greenish  variety,  for  instance,  is  set 

11 


24:2  A  POPULAR  TREATISE  ON  GEMS. 

'   with  a  greenish-blue  foil ;  the  pale  is  set  in  a  black  ground, 
like  the  diamond,  or  on  a  silvery  foil. 

Beryl  is- employed  in  jewelry  for  rings,  pins,  ear-drops, 
seals,  &c. :  but  011  account  of  its  softness  it  is  rendered 
less  lasting,  and  as  by  wearing  it  loses  all  its  beauty,  it 
does  not  command  a  high  price  in  market,  being  much 
below  that  of  the  emerald. 

A  beryl  of  a  carat,  averages  about  one  dollar  and  fifty 
cents,  and  the  price  increases  in  the  same  ratio  with  the 
number  of  carats.  The  beryl  is  subject  to  such  faults  as 
spots,  feathers,  and  fissures. 

For  the  beryl,  is  sometimes  substituted  chrysolite,  which 
is  softer,  however ;  it  is  also  imitated  by  paste,  which  ia 
likewise  softer  than  beryl. 

One  of  the  largest  transparent  beryls,  weighing  five 
hundred  and  ninety-five  carats,  was  once  in  the  possession 
of  a  mineralogist  at  Vienna.  In  1811,  a  beryl  of  fifteen 
pounds,  pure,  was  discovered  in  Brazil.  In  1825,  a  beau- 
tiful rounded  Brazilian  beryl,  of  four  pounds  weight,  was 
offered  for  sale  for  six  hundred  pounds  sterling. 

Mawe  describes  a  pure  transparent  beryl,  altogether  free 
of  faults,  seven  inches  long  antf  three  quarters  of  an  inch 
thick. 

In  1827,  a  superb  aquamarine,  weighing  thirty-five  gram- 
mes, was  found  in  the  borough  of  Mowzzinskaia,  in  Siberia, 
which  the  Russians  are  said  to  value  at  six  hundred  thousand 
francs.  A  very  remarkable  aquamarine,  of  extraordinary 
size,  ornamented  the  tiara  of  Pope  Julius  I. 

There  is  also  a  very  fine  aquamarine  in  the  Imperial 
Library  of  Paris,  on  which  there  is  a  well-executed  en- 
graving, by  Erodus,  of  Julia,  daughter  of  Titus. 

•  There  is,  according  to  Caire,  another  aquamarine  in 
London-,  weighing  five  hundred  and  forty  carats.  In  the 
Mineralogical  Museum,  of  Paris,  there  is  an  aquamarine 


BEEYL.  243 

weighing  one  hundred  and  thirty-three  grains;  and  another 
one  in  a  rough  state,  and  extremely  beautiful,  weighing 
over  twenty  carats,  for  which  15,000  francs  were  offered. 

There  are  many  of  the  intaglios  of  the  ancients  in  the 
aquamarine. 

Pliny  speaks  of  the  finest  beryls  as  those  "qui  viridatem 
piiri  maris  imitantur,"  and  hence  the  term  aquamarine  is 
applied  to  those  beryls  which  have  beautiful  shades  yf  sky- 
blue  or  mountain-green  colors. 

The  aquamarine  was  much  employed  by  the  ancients  for 
engraving  :  there  is  one  by  Qnintillius,  of  Neptune  mounted 
on  marine  horses ;  another  of  a  drunken  Hercules,  by  Hyllus. 

A  similar  intaglio,  with  terrestrial  instead  of  s^a  horses,' 
is  the  treasure  of  Odescalchi. 

The  specimen  of  beryl  on  the  frontispiece  was  the  prop- 
erty of  Baron  Struve,  Russian  ambassador  at  Hamburgh ;  it 
was  of  grass-green  color,  fifteen  inches  long  and  two  inches 
in  diameter.  A  similar,  but  smaller,  specimen,  and  more 
yellowish-green  in  color,  was  in  the  case  of  Mr.  J.  Tennant, 
of  London,  at  the  Exhibition  of  1851.  Both  are  Siberian 
beryls.  The  most  splendid  specimen,  weighing  eighteen 
and  a  half  pounds,  which  formerly  belonged  to  Don  Pedro, 
in  size  and  form,  resembles  the  head  of  a  calf,  and  exhibits 
a  crystalline  structure  on  one  side  only ;  the*  rest  is  water- 
worn,  perfectly  transparent,  and  without  a  flaw,  and  of 
a  fine  gale  bottle-green  color.  Beryls  are  frequently  ob- 
tained in  Brazil  and  Siberia  of  one  foot  in  length,  but  they 
are  commonly  very  deeply  striated  longitudinally. 

Mr.  Francis  Alger,  of  Boston,  informed  the  author  ot 
having  obtained  a  huge  beryl  crystal  nearly  perfect,  of  one 
thousand  pounds  weight,  from  Acworth,  in  New  Hampshire, 
about  fifteen  miles  from  Bellows'  Falls.  Beryls  occur  there 
in  extensive  veins  of  granite,  traversing  the  gneiss.  The 
localities  of  beryl  are  very  numerous  in  the  United  States. 


244  A  POPULAR  TREATISE  ON  GEMS. 

In  graphic  granite,  associated  with  black  tourmaline,  good 
clear  crystals  are  found  in  Bocodoniham,  and  Taphain, 
Georgetown,  Parker's  Island,  and  at  the  mouth  of  Kene- 
bec  river,  in  the  State  of  Maine ;  at  Goshen  and  Chester- 
field, Mass.,  in  irregular  crystals  of  a  pale-green  color ;  and 
transparent,  at  Monroe,  in  Conn.,  in  a  granite  vein ;  in 
Had  dam,  Conn.,  at  the  chrysoberyl  locality,  where  the 
beryls  of  yellow  and  yellowish-green  colors  are  imbedded 
with  crystals  of  chrysoberyl  and  colunibite. 


ZIRCON,    HYACINTH,    JARGON. 

'  Zircon*and  hyacinth  were  regarded  as  distinct  minerals 
until  the  improvement  in  chemical  analysis  proved  the  same 
constituents  to  exist  in  both,  particularly  zirconia,  a  peculiar 
earth:  they  are  now  considered. as  two  varieties  of  one  and 
the  same  mineral.  Zircon  is  also  called  jargon,  and  this 
name  is  either  of  Ceylonese  or  French  origin.  The  an- 
cients denominated  hyacinth,  the  gem  which  is  now  known 
by  the  name  of  carbuncle ;  their  true  hyacinth  was  a  dark 
amethyst.  The  zircon  was  formerly  used  as  a  celebrated 
medicine. 

Zircon  crystallizes  in  four-sided  prisms,  terminated  by 
four-sided  pyramids,  with  various  modifications  ;*  the  crys- 
tals are  smooth,  rough,  or  uneven;  it  occurs  likewise  in 
rounded  pebbles;  it  is  transparent  and  translucent;  pos- 
sesses double  refraction  in  a  great  degree ;  and  has  a  vivid 
vitreous  lustre,  approaching  sometimes  to  adamantine. 
Color,  from  hyacinth-red  to  yellow  and  brown ;  also,  red, 
gray,  white,  brown,  and  greenish-gray.  It  slightly  scratches 


*  See  in  the  frontispiece,  a  beautiful  American  zircon,  from  the  cabinet 
of  Dr.  J.  K.  Chilton,  of  New  York.  It  was  found  in  Buncombe  county, 
North  Carolina.  • 


ZIRCON.  245 

quartz,  but  is  attacked  by  the  topaz ;  its  streak  yields  a 
white  powder ;  specific  gravity  is  4'00  to  4'70 ;  hardness, 
7'5  ;  it  becomes  electric  by  friction ;  is  infusible  before  the 
blowpipe,  but  loses  its  color  at  a  low  heat,  the  yellowish- 
brown,  however*  becomes  redder ;  acids  do  not  act  upon 
it.  Its  chemical  constituents  are  zirconia  an<J  silica,  with 
about  two  per  cent,  oxide  of  iron,  which  is  the  coloring 
principle. 

1st.  Zircon,  called  by  jewellers  Ceylonian  zircon, — fire- 
red,  yellow,  yellowish-green,  and  gray. 

2d.  Hyacinth  is  called  by  jewellers  the  Oriental  hya- 
cinth, which  is  of  a  hyacinth-red,  deep  red,  with  a  touch  of 
the  brown,  and  sometimes  orange-yellow  color.  Zircon 
occurs  in  primitive  rocks,  and  forms  a  part  of  the  zircon 
sienite  of  Norway  and  other  countries.  It  is  also  found 
in  gneiss,  granite,  amygdaloid,  and  basalt.  It  is  likewise 
found  in  the  beds  of  rivers ;  and  there  are  localities  in 
Ceylon,  Pegu,.  Madras,  France,  Bohemia,  Saxony,  Italy, 
Siberia,  Silesia,  Scotland,  the  Canadas,  &c.  Very  fine  crys- 
tals, loose  or  attached  to  felspar,  are  found  in  Buncombe 
county,  North  Carolina.  • 

The  zircon  is  cut  with  diamond-powder,  or  emery,  on  a 
copper  wheel,  and  is  polished  with  rotten-stone  on  a  tin 
plate,  and  is  generally  cut  in  the  rose,  table,  or  thick-stone, 
.and  sometimes  the  brilliant  form.  The  foil  generally  used 
in  mounting,  is  that  corresponding  to  its  color ;  or  it  is 
mounted  in  a  black,  ground.  If  zircon  is  calcined  in  a 
crucible  filled  with  lime,  it  loses  its  color  almost  entirely, 
and  has  then  the  appearance  of  a  pale  straw-yellow  dia- 
mond, for  which  it  may  also  be  substituted.  It  is  employed 
in  jewelry  for  rings,  breastpins,  ear-rings,  or  for  ornament- 
ing watch-cases  and  snuff-boxes ;  also,  for  jewelling  watches 
and  for  supporting  fine  balances.  The  value  of  zircon  de-- 
pends  principally  upon  the  purity  of  the  color,  but  the 


246  A   POPULAR   TREATISE    ON   GEMS. 

color  of  hyacinth  is  preferable  to  that  of  zircon ;  a  carat  of 
the  former  is  worth  from  fifteen  to  twenty  dollars.  Zircon 
is  imitated  by  pastes,  which  may  easily  be  detected  by  their 
lustre,  hardness,  and  specific  gravity ;  burnt  topaz  may  be 
substituted  for  it.  • 

The  jargon  is  a  variety  of  zircon,  being  composed  of  the 
same  constituents,  and  differing  merely  in  color  from  the 
first.  It  is  mostly  of  white,  grayish-white,  and  greenish- 
white  colors,  with  tinges  of  green,  blue,  red,  and  yellow ; 
but  generally  of  a  smoky  white  color.  It  usually  occurs  in 
worn  angular  pieces,  or  in  small,  detached  crystals,  of  an 
octahedral  form.  The  crystals  are  smooth,  and  of  a  bright 
adamantine  lustre;  have  a  conchoidal  fracture,  and  double 
refraction ;  seldom  quite  transparent ;  is  harder  than  quartz, 
and  of  a  specific  gravity  of  4*3  ;  loses  its  color  when  ex- 
posed to  the  blowpipe  flame,  but  is  infusible.  It  occurs 
chiefly  in  the  sand  of  a  river  in  Ceylon,  accompanied  by 
sapphire,  spindle,  tourmaline,  &c. 

On  account  of  its  peculiar  adamantine  lustre,  it  has  often 
been  substituted  for  the  diamond,  and  a  century  ago  it  was 
regarded  as  an  inferior  variety  of  the  true  diamond,  and  few 
of  the  precious  stones  were  in  more  request,  especially  for 
mourning  ornaments,  for  which  the  dark  tone  of  its  color, 
combined  with  its  lustre,  was  supposed  peculiarly  appro- 
priate. It  has  no  value,  at  present,  in  market,  although 
it  is  still  seen  in  the  cabinet  and  in  the  collections  of 
jewellers. 

Hyacinth  differs  from  jargon  and  zircon  only  in  color, 
being  of  a  red  orange  color,  very  bright  and  transparent ; 
it  is  much  more  employed  for.  setting  than  zircon.  It 
occurs  also  in  the  sand  and  alluvial  deposits  of  some  rivers 
in  Ceylon ;  at  Espaillie,  near  Puy^  in  France ;  at  Ohlapian, 
in  Transylvania ;  occasionally  in  volcanic  tufa,  in  Auvergne, 
and  at  Vesuvius.  Siberia  affords  crystals  as  large  as  -wal- 


GAENET.  247 

nuts.     Splendid  specimens  Occur  also  in  Greenland  and 


Hyacinth  is  not  highly  prized  by  the  jeweller.  A 
large  hyacinth  of  two  hundred  and  fifty  carats,  in  the  col- 
lection of  Mr.  Herz,  of  London,  was  offered  at  a  nominal 
sum  of  fifty  pounds.  Wm.  J.  Lane,  Esq.,  of  New  York, 
has  a  beautiful  seal-stone  of  hyacinth,  which  the  author  has 
much  admired.  Mr.  Herz  has  also  a  cut  zircon  of  forty-six 
carats,  which  he  values  very  highly. 

It  is  very  doubtful  whether  the  modern  hyacinth  is  one 
of  the  number  of  stones  called  hyacinths,  vdftivdo^  by  the 
ancients.  It  is  supposed  that  the  name  was  applied  to  the 
amethyst  pr  sapphire. 


Garnet  was  well  known  to  the  ancients,  who  consid- 
ered the  carbuncle  as  the  same  mineral,  representing  the 
whole  species.  It  has  been  found  among  the  ruins  of  Rome, 
in  a  variety  of  cut  forms.  But  the  name  garnet  is  of 
modern  origin,  and  probably  was  bestowed  on  this  mineral 
from  being  found  mostly  in  grams. 

The  garnet  crystallizes  in  dodecahedral  forms,  with  many 
modifications;  the  crystals  are  sometimes  flattened  into 
tables;  it  -is  also  found  in  round  angular  grains,  and  mas- 
sive ;  the  structure  is  imperfectly  lamellar  ;  fracture,  more 
or  less  conchoidal,  sometimes  uneven  and  brittle  ;  lustre, 
shining  vitreous;  it  is  transparent  and  translucent;  the 
color  is  blood,  cherry,  or  brownish  red,  but  almost  invariably 
with  a  violet  or  blue  tinge  ;  sometimes,  however,  we  find 
garnet  of  a  yellow,  green,  brown,  or  black  color. 

The  red  garnet  scratches  quartz  faintly,  but  is  attacked 
by  topaz,  and  even  by  the  file  ;  its  powder  is  reddish-green  ; 
hardness,  6'5  to  7'5  ;  specific  gravity  if  from  3'1C  to  4'30  ; 


248  A  POPULAR  TREATISE  ON  GEMS. 

it  becomes  electric  by  friction ;  heated  by  itself,  the  garnet 
grows  darker,  but  resumes  its  color  when  cooled ;  it  fuses 
before  the  blowpipe  into  a  black  pebble.  Its  chemical 
constituents  are  silica,  alumina,  and  the  protoxides  of  iron 
and  manganese. 

Garnet  has  names  according  to  the  different  shadings  of 
color : 

1st.  Syrian  garnet,  which  is  also  called  the  Oriental  and 
precious  garnet,  almandine,  carbuncle ;  this  is  of  a  blood- 
red,  dark  crimson  color. 

2d.  Bohemian,  or  Ceylonese  garnet,  called  the  pyrope ; 
wine-red,  nearly  orange-yellow,  deep  colored. 

3d.  Vermeille,  or  Aplome,  having  a  deep  shade  of  orange- 
yellow. 

Pliny  describes  vessels  of  the  capacity  of  a  pint,  formed 
from  carbuncles — "  non  claros  ac  plerumque  sordidos  ac  sem- 
per fulgoris  horridi" — devoid  of  lustre  and  beauty  of  color, 
which  probably  were  large  common  garnets.  The  garnet 
is  also'  supposed  to  have  .been  the  hyacinth  of  the  ancients. 

Pyrope  is  described  #s  presenting  a  dark  blood-red 
color  by  reflected  light,  but  yellow  .by  transmitted  light. 
Pyrope  was  so  called  from  Ttvp,  fire,  onTopcu,  to  see,  in  allu- 
sion to  its  color. 

The  almandine,  or  precious  garnet,  is  transparent  and 
brownish-red,  while  pyrope  is  blood-red.  The"  red  gar- 
net occurs  imbedded  in  mica  slate,  granite,  and  gneiss, 
rarely  in  limestone,  chlorite  slate,  serpentine,  and  lava,  and 
is  found  in  the  greatest  perfection  in  Ceylon,  in  the  sand  ot 
rivers ;  and  in  the  alluvial  soil  of  Pegu,  Hindostan,  Brazil, 
and  Greenland ;  in  Bohemia,  in  alluvium,  near  Collin ;  in 
gneiss- at  Zbislau;  in  Tyrol,  in  the  Oetzthal,  and  on. the 
Greiner,  in  Carinthia,  Styria;  in  Switzerland;  at  Ariolo, 
Canaria,  Maggia ;  in  Hungary,  Sweden,  Norway,  Scotland, 
Spain ;  and  in  the  United  States,  in  North  Carolina,  Geor- 


GAENET.  249 

gia,  Massachusetts,  and  New  Hampshire.  Professor  Ed- 
ward Hitchcock  once  exhibited  to  the  author  some  beautiful 
cut  precious  garnets  from  Berkshire  county,  Massachusetts ; 
the  Hon.  Mr.  Clingman,  U.  S.  Senator  from  North  Caro- 
lina, has  some  very  handsome  transparent  garnets  from  his 
district  in  Buncombe  county,  North  Carolina. 

The  common  garnet  is  met  with  in  dodecahedrons,  from 
three  to  four  inches  in  diameter,  at  Fahlun  in  Sweden, 
Arendal  and  Kongsberg  in  Norway,  and  the  Zillerthal  in 
Tyrol ;  in  Moravia,  Silesia,  and  Siberia ;  in  granular  lime- 
stone at  Haslan,  near  Eger,  hi  Bohemia ;  beautiful  crystals 
of  a  rich  brownish-red  color,  disseminated  in  hornblende 
gneiss,  are  found  in  Hanover,  New  Hampshire,  in  the 
United  States;  dark  blood-red  and  splendid  dodecahedrons, 
with  peached  and  truncated  edges,  at  Franconia,  New 
Hampshire,  in  geodes,  in  massive  quartz,  calcareous  spar, 
and  magnetic  iron  ore ;  at  Carlisle,  Massachusetts,  beautiful 
geodes  of  crystals  of  transparent  cinnamon  color,  accompa- 
nying scapolite  in  white  limestone ;  at  Monroe  and  Had- 
dam,  Connecticut,  imbedded  in  mica  slate,  also  associated 
with  chrysoberyl,  beryl,  automolite,  and  columbite ;  large 
dodecahedral  crystals,  two  inches  and  more  in  diameter,  of 
a  dark  brownish-red  color,  at  New  Fane  and  Marlborough, 
in  chlorite  slate ;  also  in  mica  slate,  in  Chesterfield,  Massa- 
chusetts. 

Colophonite  is  a  granular  brown  variety,  and  is  found  in 
Arendal,  Norway,  and  forms  a  large  vein  in  gneiss  at 
Willsborough,  New  York,  on  Lake  Champlain;  a  finer 
graded  variety  of  yellow  and  red  colors  is  found  on 
Rogers'  Rock,  at  Lake  George.  The  colophonite  is  com- 
posed of  coarse,  roundish  particles,  oil-green  and  honey- 
yellow  colors,  and  often  possesses  a  fine  iridescence. 

Alloehroite  is  similar  to  colophonite,  but  the  particles 
are  impalpable  and  strongly  coherent. 


250  A  POPULAR  TREATISE  ON  GEMS. 

Grossular  has  a  pale  gooseberry-green  color  (whence 
its  name) ;  in  serpentine,  with  idocrase,  in  the  Wilni  river, 
in  Kamtschatka. 

Topazolite  is  a  honey-yellow  garnet,  in  veins  in  ser- 
pentine ;  has  small  yellow  crystals ;  found  on  the  Mussa 
Alp,  in  Piedmont. 

Aplome  presents  the  form  of  the  dodecahedron,  but 
the  facets  are  striated,  parallel  to  the  shorter  diagonal; 
its  color  is  brown,  sometimes  greenish;  from  Sahla,  in 
Sweden.  • 

Melanite,  from  peXag,  black,  occurs  in  black  dodecahe- 
drons, sometimes  modified  in  volcanic  rocks,  on  Monte 
Somma,  in  matter  ejected  by  Vesuvius ;  Frascati,  Albano, 
near  Rome,  the  Brisgau,  in  beds  on  the  older  rocks  at 
Arendel,  in  Norway. 

Pyrenaite  is  found  in  minute,  black,  symmetrical  dodec- 
ahedrons, and  was .  so  called  from  its  locality  in  the  Pyre- 
nees, and  at  the  Pic  Eves  Lids,  near  Bareges. 

Ouwarowite  bears  a  close  resemblance  to  the  green 
garnet.  It  occurs  in  transparent  emerald-green  dodecahe- 
drons, with  a  hardness  of  V'05 — harder  than  the  garnet.  It 
occurs  at  Bissersk,  in  Russia. 

The  several  varieties  of  garnet  are  quite  different  in  their 
composition ;  they  all  contain  silicate  of  alumina,  and  va- 
riable proportions  of  the  silicates  of  lime,  iron,  and  manga- 
nese, which  substances  have  the  property  of  replacing  one 
another  without  causing  a  change  of  crystalline  form.  The 
f  varieties  of  garnet  are  often  classed  as  distinct  species,  such 
as  almandine,  pyrope,  dodecahedral  garnet,  melanite,  gros- 
sular^  topazolite,  aplome,  essonite,  cinnamon-stone,  Green- 
Jandite,  pyrenaite,  colophonite,  allochroite,  Romanzovite, 
carbuncle,  and  ouwarowite.  It  is  proper  that  garnet  be 
divided  into  precious  and  common;  the  first  being  the 
transparent,  and  the  latter  the  opaque  variety.  The  pre- 


GARNET.  251 

cious  garnet,  is  again  divided,  according  to  its  transparency, 
into  almandine  and  pyrope.  As  already  stated,  the  dif- 
ferent varieties  differ  very  little,  and  as  the  only  import- 
ant species,  possessing  characters  more  distinctive  than 
others  from  the  garnet,  is  the  cinnamon-stone,  or  essonite, 
the  author  has  seen  fit  to  separate  it  from  the  garnet,  and 
to  describe  it  under  its  proper  head ;  moreover,  essonite 
is  more  used  by  jewellers,  when  cut,  than  any  of  the  other 
species  of  garnet,  and  as  it  has  of  late  become  fashion- 
able, it  may  be  well  to  give  a  fuller  description  of  the 
same. 

Garnet  was  the  carbunculus  of  the  ancients.  This  term 
was  probably  applied  also  to  the  spinelle  and  Oriental  ruby. 
The  alabandic  carbuncles  of  Pliny  were  so  called,  because 
they  were  cut  and  polished  at  Alabanda ;  hence  the  name 
almandine,  now  in  use. 

In  Bohemia,  where  there  is  a  considerable  trade  in  gar- 
nets, they  are  separated  from  the  earth  by  levigation, 
then  assorted  into  different  sizes,  afterwards  washed  again, 
and  assorted  as  to  color  and  quality,  and  according  to  the 
quantity  required  for  balancing  a  certain  weight,  as  half 
an  ounce,  they  are  called  32,  40,  76,  100;  very  seldom 
do  they  find  them  16  to  20,  weighing  together  half  an 
ounce. 

The  larger  garnets  are  cut  on  the  leaden  wheel  with  em- 
ery, or  their  own  powder,  and  polished  with  rotten-stone 
or  oil  of  vitriol,  on  a  tin  plate,  in  the  form  of  brilliants, 
roses,  table-stones,  or  in  cabochon,  or  with  two  rows  of 
facets  at  the  girdle;  and  very  often  garnets  are  brighter 
and  more  agreeable  by  excavating  them  circularly  on  the 
bottom ;  they  are  then  called  garnet-cups.  I  have  in  my 
possession  several  large  excavated  garnets,  and  I  saw  at 
Berlin,  in  1828,  such  garnets  of  two  and  three  inches  size. 

Fine  garnets  are  set  d  jour  •  others  are  set  with  a  gold 


252  A  POPULAR  TREATISE  ON  GEMS. 

or  violet  foil  at  the  base.  Smaller  garnets  are  wrought  on 
a  large  scale  in  manufactories  for  that  purpose.  They  are 
perforated  with  the  diamond,  first,  by  means  of  a  small 
point,  then  of  a  larger,  and  at  last  a  finer  point ;  one  hun- 
dred and  fifty  garnets  may  be  perforated  daily. 

The  best  garnets  are  cut  in  brilliant  iorm,  and  with  regu- 
lar facets,  on  a  plate  of  fine  sandstone,  with  sweet  oil  and 
emery.  One  man  can  finish  thirty  such  garnets. in  one  day. 
The  polishing  on  wooden  or  leaden  plates,  with  rotten-stone 
or  oil  of  vitriol,  is  performed  by  women  and  children. 
More  than  twenty  thousand  garnets  are  yearly  carried  to 
market  from  a  single  manufactory. 

Garnets  are  much  worn  in  jewelry,  *as  -rings,  breastpins, 
ear-rings,  and  necklaces;  and  sometimes  snuff-boxes  are 
cut  out  of  the  larger  ones  from  Greenland,  Syria,  or  Tyrol; 
the  inferior  pieces,  unfit  for  cutting,  are  calcined  and  re- 
duced to  powder,  and  employed  as  material  for  polishing 
other  gems. 

The  value  of  garnets  is  determined  by  their  degree  of 
perfection,  as  well  as  color,  purity,  and  size.  On  account 
of  their  peculiarly  deep  color  they  must  be  cut  very  thin ; 
and  all  such  garnets  as  retain  their  fine  color,  without  being 
cut  too  thin,  are  held  in  high  estimation,  and  stand  in  value 
near  the  sapphire.  A  Syrian  garnet  eight  and  a  half  lines 
long,  and  six  and  a  half  lines  broad,  and  cut  octangular, 
was  sold  at  the  auction  of  tne  Marquis  de  Dree  for  three 
thousand  five  hundred  'and  fifty  francs.  A  fire-red  oval 
Ceylon ese  garnet,  eleven  lines  long  and  seven  broad,  was 
sold  for  one  thousand  and  three  francs.  They  are  generally 
sold  by  the  pound,  containing  from  sixty  to  four  hundred, 
valued  at  about  eight  to  ten  dollars  per  pound ;  but  a  set 
of  one  thousand  of  the  best  selected  garnets,  well  cut,  is 
sold  at  about  sixty  dollars.  Garnet  is  harder  than  idocrase 
or  oxide  of  tin,  but  the  latter  is  heavier. 


V  253 

In  the  Mineralogical  Museum  of  the  Jardin  des  Plantes, 
in  Paris,  are  some  very  fine  garnets  with  engravings ;  one 
^s  a  mask  of  Silene,  crowned  with  vine  leaves;  another  is 
Calphurnia's  restlessness  on  the  fate  of  Caesar ;  also  the  bust 
of  Adrian,  from  the  cabinet  of  Odescalchi ;  the  dog  Syrius ; 
a  head  of  Augustus,  belonging  to  the  Prince  of  Orange. 

Garnet  is  very  well  imitated  by  pastes,  which  are, 
however,  softer  and  lighter,  and  differ  in  many  other 
respects. 

The  following  composition  yields  a  superior  imitation  of 
the  Syrian  garnet : 

To  1000  parts  strass,  add 

500     "      glass  of  antimony, 
4     "      cassius  purple, 
4     "      oxide  of  manganese. 

ESSOXTTE,  CIXXAMOX-STOXE. 

This  gem  was  formerly  considered  identical  with  hya- 
cinth, under  which  name  it  yet  passes  in  commerce  and 
among  manufacturing  jewellers,  and  in  France  it  is  called 
hyacinth  de  Ceylon;  it  is  also  called,  in  mineralogical 
works,  cannel  or  cinnamon  stone,  which  name  it  received 
from  the  Dutch  gem-dealers,  on  account  of  its  resemblance 
to  the  oil  of  cinnamon.  Werner  was  the  first  who  gave 
this  stone  the  above  name. 

*Essonite  occurs  in  crystals  and  grains;  its  fracture  is 
conchoidal  and  uneven  ;  it  is  transparent  and  translucent ; 
has  simple  refraction  of  light ;  the  lustre  is  between  vitreous 
and  resinous;  its  color  is  deep-red,  hyacinth-red,  or  or- 
ange-yellow ;  it  scratches  glass  and  quartz  indifferently, 
but  is  attacked  by  topaz;  its  powder  is  white;  specific 
gravity  is  3'5  to  3*6  ;  it  becomes  electric  by  rubbing ;  acts 
sometimes  on  the  magnetic  needle ;  fuses  easily  before  the 


254  A  POPULAR  ^REATTSE  ON  GEMS. 

blowpipe  into  a  clear  greenish  glass ;  borax  and  acids  do 
not  affect  it. 

Essonite  is  found  in  the  sand  of  rivers,  and  in  the  primi-t 
tive  rocks  of  Ceylon,  in  considerable  masses ;  also  in  Scot- 
land. 

It  is  treated  like  garnet,  by  being  cut  on  a  copper 
plate  with  emery,  and  polished  on  a  tin  wheel  with  rotten- 
stone.  It  also  receives  the  form  of  other  gems,  and  when 
set,  it  is  mounted  with  a  foil  answering  to  its  color. 

It  is  used  for  rings  and  breastpins.  Essonite*  is  distin- 
guished from  zircon  by  inferior  hardness,  smaller  specific 
gravity,  diminished  lustre,  and  simple  refraction  of  light. 
Garnet  is  heavier,  and  idocrase  is  lighter  than  essonite. 

TOURMALINE,  RUBELLITE,  SIBERITE. 

This  mineral  is  as  yet  very  little  known  among  jewellers 
and  the  trade  in  general,  although  it  has  been  in  commerce 
for  a  number  of  years  past,  but  under  other  names,  such  as 
red  tourmaline,  or  siberite,  brought  from  Siberia,  and  sold 
in  the  trade  as  Oriental  ruby. 

Tourmaline  was  first  introduced  as  a  gem  by  the  Dutch, 
who  imported  it  from  Ceylon.  Tourmaline  occurs  in 
crystals  and  crystalline  masses,  and 
its  forms  are  six,  nine,  and  twelve 
sided  prisms,  with  various  trunca- 
tions and  terminations,  which  com- 
monly differ  in  the  number  and  size 
of  the  faces  at  the  two  ends.  The 
crystals  are  long,  striated,  and  com- 
plete, or  aggregated  into  irregu- 
lar masses;  the  fracture  is  conchoidal  and  uneven,  semi- 
transparent  to  opaque.  It  has  double  refraction  of  light, 
which,  however,  is  only  visible  in  small  pieces ;  it  has  a 


TOTTRITALINE.  25  C 

vitreous  lustre ;  the  colors  are  blue,  red,  green,  and  brown, 
of  different  shades.  Several  colors  may  often  be  observed 
in  one  and  the  same  crystal,  as,  for  instance,  in  the  rubellite 
from  Paris,  in  Maine,  and  Chesterfield,  Massachusetts,  in- 
closed by  the  green  tourmaline ;  and  the  color  often  varies 
in  its  different  layers. 

Tourmaline  scratches  glass  slightly,  but  is  scratched  by 
topaz ;  its  powder  is  white ;  its  specific  gravity  is  3*0  to  3'3 ; 
it  becomes  electric  by  rubbing,  that  end  having  the  great- 
est number  of  faces  being  positive,  the  other  negative. 
When  tourmaline  is  heated  it  exhibits  polarity,  the  iUbst 
modified  extremity  becoming  positive  and  the  other  nega- 
tive. In  this  particular  it  resembles  other  hemihedrically 
modified  crystals.  At  a  certain  temperature  it  loses  its 
polarity,  but  exhibits  it  again  on  cooling ;  its  polarity  con- 
tinues with  the  decrease  of  temperature  until  it  reaches  32° 
Fahr. ;  a  continued  increase  of  cold  re-excites  the  electric 
polarity,  though  with  reversed  poles ;  if  the  excited  crystal 
be  broken,  «ach  part  thus  produced  will  equally  possess 
polarity,  and  even  in  the  powdered  state  it  retains  its  pyro- 
electricity.  Before  the  blowpipe  it  intumesces  more  or 
less,  does  not  fuse,  but  vitrifies  on  the  edges ;  turns  green, 
then  yellow,  then  red,  then  milk-white,  .then  blue,  and 
then  black.  Borax  dissolves  it  pretty  easily  into  a  clear 
bead. 

The  chemical  composition  of  tourmalines  varies  greatly : 
they  are  composed  of  alumine,  silica,  oxide  of  iron,  oxide 
of  manganese,  and  boracic  acid ;  those  from  different  lo- 
calities contain  either  potash,  soda,  lithia,  or  calcia.  The 
following  are  the  different  varieties,  not  -including,  how- 
ever, the  white,  yellow,  and  black  tourmaline,  or  schorl,  they 
not  being  used  as  gems  : 

1.  Siberian  tourmaline  (siberite,  rubellite,  apyrite),  which 
is  of  a  carmine  or  hyacinth  red,  purple  or  rose  red,  passing 


256  A    POPULAR   TREATISE   ON    GEMS. 

into  violet ;  sometimes,  by  looking  through  in  one  direc- 
tion, the  red  color  changes  into  a  blue  color. 

2.  Indicolite  (Brazilian  sapphire),  of  an  indigo,  lazulite, 
or  Prussian  blue  color. 

3.  Brazilian  tourmaline  (Brazilian  emerald),  of  a  grass- 
green  or  olive-green  color. 

4.  Ceylonian  tourmaline  (Ceylon  chrysolite),  of  a  green- 
ish-yellow color. 

5.  Electric  schorl,  of  a  yellowish,  reddish,  liver,  or  black- 
ish brown  color. 

^mrmaline  occurs  in  rocks,  such  as  granite  in  layers 
and  gahgues,  and  in  boulders ;  it  also  occurs  in  the  beds 
of  rivers,  and  the  localities  are  Siberia,  St.  Gothard,  Ceylon, 
Brazil,  Sweden,  Saxony,  and  Moravia.  In  the  United 
States,  tourmalines  are  abundant,  but  there  are  very  few 
localities  of  the  betfer  varieties,  as  those  at  Paris  in  Maine, 
and  Chesterfield  and  Goshen  in  Massachusetts. 

The  specimen  of  a  crystal  of  rubellite,  from  Paris,  Me., 
on  the  frontispiece,  is  a  perfect  prism,  is  dark^  red  on  the 
inside  and  dark  green  on  the  outside,  and  belongs  to  Prof. 
Charles  U.  Shepard,  of. New  Haven,  who  exhibited  it  in 
thje  New  York  Exhibition  in  1853.  There  are  several 
beautiful  green  and  red  transparent  tourmaline  crystals, 
from  the  same  locality,  in  the  mineralogical  museum  of 
Yale  College,  from  the  collection  of  the  late  Baron  Lederer, 
Austrian  consul  in  this  city. 

The  yellow  tourmaline,  from  Ceylon,  is  but  little  inferior 
to  the  real  topaz,  and  is  often  sold  for  that  gem.  The  green 
tourmaline,  when  transparent,  is  often  highly  prized.  ' 

The  Siberian  red  tourmaline,  called  .siberite,  is  cut  in 
cabochon,  and  exhibits  then  a  milk-white  chatoyant  lustre. 

The  black  tourmaline  is  called  schorl.  The  localities  of 
tourmaline  are  quite  •  numerous :  large  size  black  tour- 
malines are  found  in  Greenland  at  Hovelberg,  in  Bavaria 


TOURMALINE.  257 

near  Bodenmays,  at  Karinbrida  in  Sweden,  and  near  Bo- 
vey  in  Devonshire.  Small  brilliant  crystals  are  met  with, 
imbedded  in  decomposed  felspar,  at  Andreasberg,  in  the 
Hartz  mountains,  forming  the  variety  called  aphrigite.  Ru- 
bellite  occurs  in  a  species  of  lithomarge,  near  Ekaterinen- 
burg  in  Siberia  ;  pale  yellowish-brown  crystals  are  found  in 
talc  at  Windiscji  Kappell,  in  Carinthia ;  white  and  varie- 
gated colored  specimens  come  from  St.  Gothard  and  Sibe- 
ria, the  first  imbedded  in  dolomite. 

In  the  United  States,  some  magnificent  specimens  of  red 
and  green  tourmalines  were  found  in  1829  at  Paris,  State 
of  Maine ;  some  transparent  crystals  from  that  locality  ex- 
ceed two  inches  in  diameter,  and  very  frequently  one  inch, 
and  present  a  clear  red  color  internally,  surrounded  by 
green,  or  are  red  at  one  extremity  and  green  at  the  other. 
Blue  and  pink  varieties,  most  commonly  imbedded  in  lep- 
idolite,  are  yet  occasionally  found  in  this  locality. 

Red  and  green  tourmalines  occur  also  at  Chesterfield, 
Mass.,  in  a  narrow  vein  of  granite  traversing  gneiss ;  the 
crystals  are  commonly  small  and  curved,  nearly  opaque, 
and  exceedingly  frangible.  Green  crystals  often  contain 
distinct  prisms  of  a.  red  color,  especially  when  they  occur  in 
smoky  quartz ;  blue  tourmalines  also  occur  at  this  locality, 
and  are  accompanied  by  albite. 

The  Russian  Mineralogical  Museum  was  supplied,  in 
1832,  by  its  minister,  Baron  Crudner,  with  specimens  of 
fifty  pounds  weight,  containing  the  rock  of  green  and  red 
tourmalines,  from  the  Chesterfield  locality. 

At  Goshen,  Mass.,  similar  varieties  occur,  and  the  blue 
tourmaline  is  met  with  in  greater  perfection ;  very  perfect 
crystals,  of  a  dark-brown  color,  occur  imbedded  in  mica 
slate,  at  Monroe,  Conn. ;  the  crystals  are  commonly  from 
one  to  two  inches  long,  and  nearly  as  broad,  and  uniformly 
they  are  perfectly  terminated  at  the  two  extremities. 


258  A   POPULAR   TREATISE   ON   GEMS. 

Haddam,  Conn.,  also  affords  fine  black  crystals,  and  some 
of  large  size ;  they  are  profusely  mingled  in  a  mica  slate, 
and  associated  with  anthophylite  and  hornblende.  A  cin- 
namon-brown variety  is  met  with  at  Gouverneur,  N".  Y., 
imbedded  with  quartz,  and  also  associated  with  scapolite, 
apatite,  and  sphene,  in  granular  limestone.  These  crystals 
are  very  often  highly  modified,  and  occasionally  exhibit  the 
faces  of  a  scalene  dodecahedron  in  addition  to  the  terminal 
planes.  Similar  specimens  occur  at  Grenville,  Lower  Can- 
ada, and  Newton,  N".  J.,  associated  with  corundum,  spinelle, 
and  rutil ;  and  at  Kingsbridge,  N".  Y.,  and  Carlisle,  Mass., 
with  garnet. 

The  red  tourmaline,  when  transparent  and  free  from 
cracks  and  fissures,  admits  of  a  high  polish,  and  forms  a 
most  beautiful  and  costly  gem. 

It  has  been  supposed  that  tourmaline  was  known  to  the 
ancients  under  the  name  of  lyncurium  (Aw/covptov),  which 
is  described  as  having  electrical  properties;  this  name, 
however,  was  more  probably  applied  to  some  variety  of 
amber,  which  was  so  called  from  its  supposed  origin  from 
the  urine  of  the  lynx.  The  identity  of  the  red  tourmaline 
with  the  hyacinth  of  the  Greeks  is  more  probable ;  the 
other  varieties  were  either  unknown,  or  possibly  connected 
under  a  common  name  with  other  species  of  the  same  color. 

Tourmaline  received  no  attention  from  the  moderns  till 
Lemery,  in  1717,  published  his  discoveries.  The  word 
tourmaline  is  a  corruption  of  the  name  for  this  mineral  at 
Ceylon,  whence  it  was  first  brought  into  Europe. 

The  name  schorl,  which  has  been  applied  to  the  black 
tourmaline  and  some  other  mineral  species,  is  reported  to 
have  been  derived  from  Schorland,  the  name  of  a  village  in 
Saxony,  which  afforded  specimens  of  this  variety. 

Tourmaline  is  cut  on  a  brass  or  leaden  wheel  with 
emery,  and  polished  with  rotten-stone  on  a  tin  plate ;  it  re- 


QUABTZ.  259 

ceivcs  varfctis  forms,  such  as  the  step  and  table  cut.  If  of 
a  pure  color,  it  is  set  d  jour,  otherwise  with  a  foil  corre- 
sponding to  its  color ;  but  the  electric  schorl  is  sometimes 
set  so  that  it  can  be  removed  from  its  mounting  to  be  used 
in  performing  experiments.  The  value  of  tourmaline  de- 
pends upon  its  color,  purity,  and  size.  The  siberite  and  . 
rubellite  stand  highest  in  estimation.  A  siberite,  as  large 
as* five  lines,  is  worth  about  one  hundred  and  fifty  dollars; 
and  one  of  four  to  twelve  lines,  good  color  and  pure,  is 
worth  about  fifteefl  hundred  dollars.  The  rubellite  from 
Paris,  Maine,  has  become  very  rare,  and  it  is  muqh  to  be 
regretted  that  no  more  attention  is  paid  to  obtaining  a 
fre§h  supply,  as  the  crystals  are  of  an  exceedingly  fine 
purple  color,  and  perfectly  transparent.  I  have  a  few  pol- 
ished rubellites  and  green  tourmalines  in  my  cabinet,  which 
I  value  equally  as  high  as  any  gems. 

The  dark-green  tourmalines,  six.  lines  long  and  four 
broad,  are  sold  in  Paris  for  eighty  francs,  and  the  light- 
green,  of  the  same  size,  for  forty  francs.  The  most  splen- 
did siberite  is  at  the  British  Museum,  having  been  pre- 
sented by  the  King  of  Ava  to  Colonel  Symes ;  it  is  valued 
at  one  thousand  pounds  sterling. 

Tourmalines  may  be  readily  distinguished  from  other 
gems  or  pastes,  which  are  sometimes  substituted  for  them, 
by  their  property  of  assuming  polaric  electricity  after  being 
heated.  .  . 

QUAKTZ, 

This  mineral  is  diffused  all  over  the  globe.  Its  varieties 
are  very  numerous,  and  many  of  them  are  employed  in 
jewelry  and  for  divers  ornamental  purposes.  It  occurs 
massive,  in  concretions,  in  confused  crystalline  masses,  and 
in  crystals,  of  which  the  form  is  the  six-sided  prism,  termi- 
nated by  six-sided  pyramids;  also  the  dodecahedron,  or 


260  A   POPULAR   TREATISE    ON   GEMS. 

double  six-sided  pyramid.  Quartz  scratches^rlass  and 
felspar,  but  is  attacked  by  topaz.  Its  hardness  is  7*0. 
and  its  specific  gravity,  2*5  to  2*7  ;  it  is  transparent,  and 
possesses  a  vitreous  lustre ;  becomes  electric  by  rubbing ; 
is  infusible  before  the  blowpipe.  Acids,  except  the-  fluoric 
acid,  do  not  act  upon  it.  Silica  is  the  only  essential  com- 
ponent part  of  quartz,  but  some  varieties  contain  iron,  alu- 
mine,  or  lime. 

ROCK   CRYSTAL. 

This  mineral  was  knowrn  in  early  ages.  It  was  highly 
esteemed  by  the  Greeks  on  account  of  its  purity  and  very 
regular  formation.  Theophrastes  states  that  it  was  "cut 
principally  as  seals,  and  the  ancients  made  great  use  of  it 
for  ornaments,  particularly  before  the  art  of  making  glass 
had  reached  much  perfection.  Among  the  many  vessels 
which  were  cut  in  the  form  of  cups,  vases,  &c.,  were  two 
fine  bowls  and  chalices  in  the  possession  of  the  tyrant  ]&"ero, 
who  purchased  them  at  a  large  sum.  Rock  crystal  was  also 
used  as  a  medicine. 

It  is  found  crystallized,  in  the  primitive  form,  which  is 
the  rhomboid,  extended  to  a  six-sided  pi-ism ;  and  in  a  great 
variety  of  forms  and  modifications,  such  as  with  a  trunca- 
tion or  replacement  of  the  edges,  or  solid  angles,  &c.  It 
is  frequently  found  in  groups,  also  in  the  cavities  of  other 
minerals,  or  in  incrustations,  as  small,  but  very  perfect 
crystals,  the  pyramidal  terminations  of  which  have  a  high 
polish,  and  the  specimen*  appearing  as  if  it  were  studded 
with  gems.  Many  specimens  of  this  description  were 
brought  from  Vermont  a  few  year's  ago,  and  were  eagerly 
purchased  by  the  jewellers  of  this  city  for  rings,  ear- 
rings, and  breastpins.  Rock  crystal  has  a  conchoidal  frac- 
ture ;  is  translucent  and  transparent ;  possesses  a  double 
refraction  of  light;  a  perfect  vitreous  lustre;  is  limpid, 


ROCK    CRYSTAL.  261 

white,  brown,  bla*ck,  or  yellow;  scratches  glass;  specific 
gravity,  2'65.  The  electricity  acquired  by  rubbing  lasts 
for  thirty  minutes.  Before  the  blowpipe,  when  colored,  it 
becomes  limpid.  The  following  varieties  of  it  are  made 
known  by  their  names  and  characters : 

1.  The  pseudo  diamond  (Bohemian  or  occidental  dia- 
mond), which  is  the  limpid,  colorless  rock  crystal,  cut  and 
polished. 

2.  The  iridescent  quartz  is  that  variety  of  rock  crystal, 
the 'interior  of  which  is  replete  with  fissures  and  cracks,  so 
that  the  refraction  of  the  rays  of  light  produce  the  rainbow 
colors. 

3.  Citron    (Bohemian  topaz,   occidental  topaz,   yellow 
quartz,  Scotch  pebble),  which  is  of  a  pale,  ochry,  gold, 
whitish,  lemon,  or  brownish  yellow  color.     The  false  cairn- 
gouram  of  Brazil  is  a  beautiful  variety  of  yellSw  quartz. 

4.  Smoky  topaz  (cairngouram  or  true  Scotch  pebble, 
brown  quartz,  smoky  quartz)   is  of  a   smoky  or   brown 
color. 

5.  Morion  is  of  a  charcoal-black  or  brownish-black  color. 

6.  Hair  or  needle  stone,  or  such  rock  crystal  as  has,  in  its 
interior,  foreign  substances,  as  rutil  (red  oxide  of  titanium), 
manganese,  iron,  chlorite,  amianthus,  or  asbestos.     When 
the  stone  is  so  cut  as  to  represent  the  hair  or  needles  in  an 
upright  position,  they  are  called  either  Venus'  hair  (cheveux 
de  Venus) ,  or  Love's  arrows  (flbches  cf  amour). 

Rock  crystal  occurs  in  gangues,  or  rock  cavities,  in  the 
oldest  geological  formations ;  it  is  also  occasionally  found 
in  some  modern  rocks. 

The  mountain  of  Cairngouram,  in  Aberdeenshire,  Scot- 
land, has  furnished,  and  still  continues  to  afford,  many  fine 
specimens  of  smoky  quartz.  The  lapidaries  of  Edinburgh 
always  meet  with  a  ready  sale  of  this  far-famed  stone 
among  the*  Scottish  gentlemen,  as  the  native  produce  of 


262          A  POPULAR  TEEATISE  ON  GEMS. 

their  country.  •  Many  very  beautiful  sets  of  the  Cairjigou- 
ram  were  exhibited  in  the  London  Exhibition. 

A  group  of  rock  crystal,  in  the  museum  of  the  univer- 
sity of  Naples,  weighs  nearly  half  a  ton. 

The  black  limestone  of  Quebec  affords  fine  crystals  of 
quartz.  In  the  State  of  New  York,  quartz  crystals,  remark- 
ably clear  and  perfect',  from  the  size  of  a  pin's  head  to  four 
inches,  are  found  in  many  localities.  Diamond  Island,  in 
La*ke  George,  is  a  lamed  spot ;  Gouverneur,  N.  Y.,  affords 
splendid  dodecahedral  crystals,  associated  with  an  irides- 
cent crystallized  specular  iron.  At  the  Notch  of  the  White 
Mountains,  N.  H.,  and  at  the  locality  of  tourmaline  at  Paris, 
Maine,  handsome  crystals  of  brown  and  smoky  quartz  have 
been  obtained. 

•At  Trentop  Falls,  in  the  State  of  New  York,  very  per- 
fect and  completely  terminated  transparent  crystals  are 
found,  with  their  endless  modifications,  some  of  them  five 
inches  long,  and  some  containing  drops  of  water.  It  is 
also  found  at  Windham,  Vermont,  where  the  drusy  variety 
occurs,  which  is  extremely  beautiful,  and  of  variegated 
colors.  About  twenty  years  ago  it  had  a  great  many  ad- 
mirers, and  was  generally  worn  in  brooches,  rings,  &c. 
It  is  also  found  in  Maryland,  Massachusetts,  and  on  the 
Catskill  mountains. 

V 

Rock  crystal  is  obtained  in  Switzerland,  and  some  other 
countries,  by  mining;  those  cavities  geologically  or  me- 
chanically traced  from  the  quartz  veins,  are  sounded  by 
miners  in  granite  veins  or  other  rocks,  by  means  of  in- 
struments, and  when  hollow,  extensive  preparations  are 
made  for  procuring  the  whole  produce  of  the  cavities, 
which  sometimes  amounts  to  several  tons.  It  is  likewise 
procured  from  the  sand  of  rivers,  and  it  passes  then  under 
the  name  of  flints ;  also,  from  gangues  or  veins  of.  other  min- 
erals. The  smaller  and  clearer  transparent  ones  are  gener- 


BOCK   CRYSTAL.  263 

ally  employed  in  jewelry  and  for  ornaments ;  but  the  larger 
specimens  are  first  assorted  and  then  split  or  cleaved,  and 
the  smaller  pieces  are  sawed  through  with  a  copper  wire, 
emery,  and  oil,  into  the  desired  sizes,  when  they  are  ready 
for  being  cut  on  copper  or  leaden  discs,  with  emery  and 
water,  and  polished  on  tin  plates  with  rotten-stone,  putty, 
bole,  or  other  fine  powder;  or  they  may  be  polished  on 
wooden  wheels,  lined  with  fur  or  leather.  The  forms  which 
they  generally  receive  from  the  lapidary,  are  the  brilliant, 
rose,  or  table.  The  iridescent  quartz,  and  the  hair  or 
needle  stones,  are  only  cut  concave.  Those  specimens  that 
"have  a  full  pure  wine-yellow  color,  are  best  cut  in  steps. 
When  mounted,  they  are  either  d  jour\  or  with  a  black 
foil.  Those  which  are  spotted,  or  of  an,  irregular«color, 
may  be  discolored  by  careful  calcinati<ft  in  crucibles,  with 
lime,  sand,  or  pearlash,  which  process  likewise  increases  the 
lustre.  The  crystal  may  be  bored  with  a  diamond  point, 
also  engraved,  and  figures  may  be  etched  in  it  by  means  of 
fluoric  acid.  It  is  mostly  used  for  pins  and  rings ;  also,  for 
the  base  of  doublets;  likewise,  for  a  very  great  variety  of 
ornaments,  such  as  seals,  gems,  snuff-boxes,  cane-heads,  &c. ; 
also  for  imitating  the  real  gems,  by  being  colored  and 
immediately  immersed  in  a  solution  of  coloring  water, 
whereby  the  color  is  very  closely  imitated.  It  is  moreover 
the  base  of  all  the  pastes  or  strass.- 

Its  value  is  by  no  means  so  high  as  formerly,  when  the 
demand  for  it  was  great  for  setting  in  buckles,  buttons, 
&c.  Articles  made  of  large  pieces  of  it,  or  those  con- 
taining slender  needles,  hair,  moss,  incrustation,  or  imita- 
tion of  other  substances,  are  yet  somewhat  esteemed.  In 
their  natural  state,  if  quite  clear,  as  they,  are  received  from 
Madagascar,  Switzerland,  and  Brazil,  they  are  sold  for  from 
one  to  ten  dollars  per  pound ;  but  when  cut  for  seal-stones, 
or  breastpins,  they  are  sold  mostly  by  the  jewellers  of  this 


264  A   POPULAR   TREATISE    ON   GEMS. 

country  as  white  topaz,  and  command  a  fair  price.  Well- 
cut  seal-stones  are  sold  at  from  five  to  twenty  dollars. 
Those  of  the  brilliant-cut  are  sold  at  from  fifty  cents  to  a 
dollar  a  piece.  The  largest  rock  crystal  is  said  to  be  in  the 
collection  of  M.  Rafaelli,  artist,  at  Rome, — and  a  large  can- 
delabra of.  iridescent  quartz,  is  in  the  Vatican.  The  proprie- 
tors of  the  American  Museum  of  this  city,  can  boast  of 
having  one  of  the  largest  specimens  of  rock  crystal  from 
Brazil.  It  weighs  two  hundred  and  twelve  pounds,  is  two 
feet  and  a  half  high,  and  one  foot  in  diameter,  and  is  a 
perfect  six-sided  prism. 

Two  large  crystals  of  quartz,  attached  by  one  of  the- 
vertical  faces,  the  crystals  being  each  two  and  a  half  feet 
high  by  eight  inches  in  diameter,  wrere  exhibited  by  the 
Duke  of  Devonshine,  at  the  London  Exhibition,  in  1851. 
The  pyramidal  summits  of  these  crystals,  which  rise  nearly 
a  foot  above  the  prism,  are  completely  transparent,  but  the 
prisms  are  cloudy.  These  magnificent  crystals  were  ob- 
tained from  the  Alps,  having  been  discovered  during  the 
formation  of  the  road  over  the  Simplon,  in  a  cutting  made 
through  the  old  rocks.  I  saw  a  most  magnificent  chandelier 
of  rock  crystal  in  the  Tuileries,  which  is  said  to  have  cost  one 
hundred  thousand  francs.  The  clearest  rock  crystal  comes 
from  the  island  of  Madagascar,  in  blocks  weighing  from 
fifty  to  one  hundred  pounds.  In  Switzerland,  and  the  prov- 
ince of  Auvergne,  in  France,  very  fine  specimens  may  be 
had.  The  Bristol,  Buxton,  Cornish,  and  Irish  diamonds, 
which  are  all  pyramidal  crystals -of  quartz,  are  known  all 
over  the  world. 

A  specimen  of  rock  crystal  in  the  Museum  of  Natural 
History,  at  Paris,  measures  three  feet  in  diameter,  weighs 
nearly  eight  hundred  pounds,  and  was  found  at  Fischbach, 
in  France.  9 

Rock   crystal  may  be  easily  distinguished  from  white 


BOCK    CRYSTAL.  265 

paste,  called  strass,  as  the  latter  is  heavier,  on  account  of 
.the  metallic  oxides  contained  in  the  composition. 

A  very  remarkable  phenomenon  in  quartz  is  exhibited 
by  the  fluid  drops  -which  are  contained  in  many  speci- 
mens. They  occupy  small  cavities,  and  evince  their  pres- 
ence, on  turning  the  specimens,  by  the  motion  of  the  accom- 
panying air-bubble,  like  the  bubble  in  a  spirit-level.  These 
cavities  are  sometimes  of  considerable  size.  Jacobson,  of 
Copenhagen,  possesses  a  geode  of  [quartz  an  inch  and  a 
quarter  long,  which  contains  at  least  half  a  cubic  inch  of 
fluid.  Mr.  Allen  also  describes  a  crystal  of  amethyst  in  his 
collection,  which  contains  four  cavities  partially  filled  with 
this  peculiar  fluid.  At  a  temperature  of  eighty-three  de- 
grees the  fluid  dilates  and  entirely  fills  all  the  cavities,  and 
as  it  re-appears  on  cooling,  an  ebullition  is  apparent.  Sir 
David  Brewster  has  ascertained  that  the.  fluid  is  not,  as 
was  supposed,  water,  but  of  an  oleaginous  nature,  from 
twenty  to  twenty-five  times  thinner  than  water.  A  consid- 
erable number  of  specimens  containing  the  fluid  were 
carefully  examined,  and  he  found  that  one  part  of  the  fluid 
is  volatile  at  twenty-seven  degrees,  and  the  other  was  a 
fixed  oil.  Prof.  Dana  has  lately  named  the  "former,  crypto- 
line,  and  the  latter,  brewsterline.  There  is  a  great  difference 
in  the  specific  gravity  of  both  liquids.  The  more  dense 
yields  a  transparent  yellow  resinous  globule,  which  absorbs 
the  humidity  of  the  atmosphere,  is  insoluble  in  water  and 
alcohol,  but  dissolves  in  hydrochloric,  and  nitric  acids. 

Occasionally  a  bituminous  fluid,  resembling  napththa,  is 
contained  in  the  cavities  of  quartz. 

A  very  peculiar  gelatinous  substance,  appearing  to  be 
silica  in  solution,  has  been  observed  on  breaking  open 
geodes,  and  the  production  of  a  species  of  chalcedony  from 
the  subsequent  evaporation,  has  also  been  observed.  But 
the  nature  of  the  solvent  of  silica  is  not  yet  fully  ascer- 

12 


' 


266  A  POPULAR  TREATISE  ON  GEMS. 

tained.     It  is,  however,  held  in  solution  in  the  hot  waters 
of  the  Geysers  of  Iceland,  whose  solvent  power  is  supposed  - 
to  be  due  to    the    presence    of    a  small  quantity  of  alkali 
and  their  high  temperature.      The    Geysers   have    covered 
the  part  of  Iceland  in  their  vicinity  with  a  silicious  sinter1. 

The  pseudomorphous  quartz,  from  North  Carolina,  con- 
tains fluids  in  large  quantities  in  its  cavities. 

Two  pieces  of  quartz  rubbed  together  in  the  dark,  emit  a 
phosphorescent  light  and  a  faint  empyreumatic  odor. 

AMETHYST. 

This  gem  has  been  known  sinc$  the  earliest  ages  of 
Greece  and  Rome ;  the  name  is  of  Greek  origin.  The 
ancients  believed  that  wine  drank  from  tm  amethyst  cup 
would  not  intoxicate ;  hence  its  name,  expressive  of  that 
belief — a/K0wn>s-,  from  a,  not ;  pcd™,  to  intoxicate.  As  re- 
gards the  color,  Pliny  says  :  "ad  riciniam  crystalli  descen- 
det  albicante  purpurae  defectu,"  purple  gradually  fading  into 
white.  This  is  not,  however,  the  only  amethyst  of  the 
ancients ;  the  violet-colored  sapphire,  the  violet  fluor  spar, 
("  sculptaris  faciles,"  easily  graven — Pliny,)  and  some  other 
purple'  species  were  designated  by  the  same  name.  It  has 
also  been  supposed  that  'garnet  came  under  the  same  de- 
nomination. This  name  occurs  in  Scripture,  being  that  of 
the  ninth  stone  in  order  on  the  high  priest's  breast  plate  of 
judgment,  with  the  name  Issachar  engraved  thereon. 
Amethysts  were  always  used  for  engraving.  The  bust  of 
Trajan,  in  the  Royal  Library,  at  Paris,  and  the  Apollo 
Belvidere,  the  Farnese  Hercules,  and  the  group  of  the  Lao- 
coon,  are  splendid  specimens  of  it.  It  occurs  massive  in 
boulders,  or  in  hexahedral  prismatic  crystals,  terminated 
by  hexahedral  pyramids.  Its  crystals  are  rarely  as  distinct 
as  those  of  quartz,  being,  for  the  most  part,  latterly  aggre- 


AMETHYST.  267 

gated  by  the  whole  prism,  the  terminal  pyramids  alone 
being  separated  from  each  other ;  its  fracture  is  from  con- 
choidal  to  splintry ;  it  is  transparent  to  translucent;  of  a 
vitreous  lustre ;  color  of  a  high  and  dark  violet  blue,  and 
from  its  richest  tinge  to  almost  colorless,  in  one  and  the 
same  specimen.  It  scratches  white  glass,  gives  fire  with 
steel,  but  yields  to  the  file.  Its  specific  gravity,  2-75  ;  be- 
comes electric  by  rubbing,  which  lasts,  however,  but  half 
an  hour.  Before  the  blowpipe  it  loses  its  color.  Its  com- 
ponent parts  are  pure  quartz,  colored  by  manganese  and 
iron.  It  occurs  in  veins  of  the  older  formations,  studding 
the  interior  of  agate  balls  or  geodes  in  tho  amygdaloid  and 
trap  rocks  of  Hungary,  Silesia,  Saxony,  Tyrol,  Oberstein ; 
and  as  boulders  of  splendid  specimens  in  Ceylon,  Siberia, 
and  Brazil.  It  is  wrought  in  the  same  manner  as  rock 
crystal,  being  cut  on  a  copper  wheel  with  emery,  and  pol- 
lished  on  a  tin  plate  with  rotten  stone.  In  order  to  raise 
its  lustre,  many  facets,  and  very  frequently  those  of  a  rose- 
diamond,  are  given  to  it  in  cutting.  It  is  sometimes  cut  in" 
the  form  of  a  brilliant,  and  when  set  is  supplied  with  a  blue 
or  red  foil,  provided  the  amethyst  is  pale,  for  the  deep- 
colored  ones  do  not  require  any  artificial  assistance.  It  is 
used  in  almost  every  description  of  jewelry,  such  as  rings, 
ear-rings,  and  breastpins ;  but  it  is  set  in  necklaces  to 
the  best  advantage,  and  is  the  only  colored  gem  which 
may  be  worn  with  mourning,  an  advantage  which  adds 
'to  its  value.  The  amethyst  is  no  longer  held  in  such 
estimation  as  formerly,  but  the  color,  when  intense  and 
uniform,  as  also  the  size,  contribute  greatly  to  its  value ; 
and  good  well-cut  amethysts,  of  one  carat,  are  worth  from 
three  to  five  dollars,  and  so  on,  in  proportion  to  their  size ; 
an  amethyst  fifteen  lines  long  and  eleven  lines  broad,  ex- 
quisitely fine,  was  valued  at  five  hundred  dollars. 

The  best  amethysts  now  in  commerce  come  from  Cey- 


268  A  POPULAR  TREATISE  ON  GEMS. 

Ion,  Siberia,  and  Brazil;  the  first  are  commonly  called 
Oriental  amethysts,  which,  however,  must  be  carefully 
distinguished  from  a  much  more  valuable  gem,  the  true 
Oriental  amethyst,  which  is  the  violet  .sapphire.  I  have 
in  my  collection  a  quantity  of  the  Brazilian  amethysts, 
which  are  of  an  intense  violet  color,  and  of  a  very  large 
size. 

Amethysts  occur  also  at  Pic  Bay,  and  at  Gorgontwa,  Lake 
Superior,  crystallized  in  trap ;  also  at  Bristol,  Rhode  Island, 
and  occasionally  throughout  the  trap  region  of  Massachusetts 
and  Connecticut. 

The  amethyst,  is  valued  by  the  jeweller  in  proportion 
to  the  dcpthr  richness,  and  uniformity  of  its  color,  and 
its  perfect  transparency ;;  it .  forms,  then,  a  stone  of  ex- 
quisite beauty,  its  color  being,  perhaps,  more  generally 
attractive  than  that  of  any  other  gem,  especially  as  it  may 
be  obtained  of  as  large  a  size  as  can  be  conveniently  worn. 
It  is  worn  by  priests,  bishops,  and  pontifical  dignitaries- 
as  a  ring-stone  set  with  brilliants.  Like  many  other  stones, 
it  is  less  brilliant  by  candle-light,  and  it  appears  at  all 
times  to  best  advantage  when  surrounded  with  pearls  and 
set  in  gold. 

Amethyst  has  lately  been  employed  by  the  cameo-cutters 
of  Paris,  for  cameos  and  intaglios ;  the  head  is  cut  at  the 
collet,  which  is  the  thick  part  of  the  stone,  and  the  crown 
having  diamond  facets  produces  a  fine  effect. 

•The  amethyst  is  often  imitated  by  fluor  spar  or  violet- 
blue  lime  spar;  both,  however,  are  softer  than  amethyst ; 
the  liine  is  lighter,  and  the  fluor  is  heavier  than  amethyst. 
But  it  is  imitated  very  strikingly  by  pastes,  so  that  with 
great  difficulty  the  real  is  to  be  distinguished  from  the 
imitation;  the  latter,  however,  is  somewhat  heavier,  on  ac- 
count of  the  metallic  oxides  contained  in  the  composition* 
The  following  is  the  best  receipt  for  imitating  the  amethyst : 


COMMON    QUARTZ.  2G9 

1000  parts  of  strass, 

8  •     "         oxide  of  manganese, 
0'2       "         purple  of  cassius,  and 
.500       "         oxide  of  cobalt, 

One  of  the  largest  geodes  of  amethyst  was  brought  into 
England  in  1819,  weighing  one  hundred  ami  fifty  pounds; 
it  was  two  feet  long  and  fourteen  inches' broad,  and  con- 
tained most  magnificent  crystals,  of  the  deepest  violet  color. 
On  account  of  having  been  set  down  at  too  low  a  price  at 
the  custom-house,  which  was  sixty-five  pounds  sterling,  it 
was  confiscated. 


COMMON    QUARTZ. 

But  a  few  varieties  of  the  common  quartz  are  used  in 
jewelry,  which  are :  the  Rose  Quartz,  the  Oafs-eye,  the 
Prase,  and  the  Avanturine, 

Rose   Quartz, 

This  mineral  generally  occurs  massive;  it  is  semi-trans- 
parent, and  translucent  on  the  edges ;  has  a  vitreous  lustre ; 
conchoidal  and  splintry  fracture ;  is  of  a  rose-red  color  ;  some- 
times giving  a  lustre  of  mother-of-pearl.  It  scratches  glass; 
has  a  specific  gravity  of  2*64  to  2*67;  its  color,  which  is 
derived  from  the  oxide  of  manganese,  becomes  paler  before 
the  blowpipe. 

Rose  quartz  occurs  in  gangues  of  granite  and  gneiss,  par- 
ticularly fine  in  Sweden,  Bavaria,  Bohemia,  and  Siberia ; 
also  a  beautiful  dark  color  in  New-Hampshire  and  Massa- 
chusetts. 

Rose  quartz  is  cut  and  polished  for  jewelry ;  such  as 
rings,  breastpins,  and  snuff-boxes;  it  is  cut  on  a  copper 
wheel  with  emery,  and  is  polished  with  rotten,  stone  and 
putty,  on  a  tin  plate,  receiving  the  form  of  a  cabochon  or 


270  A  POPULAR  TREATISE  ON  GEMS. 

table,  and  when  set  requires  a  foil,  colored  by  carmine  or 
solution  of  gold,  as  it  fades  when  exposed  a  long  time  to 
the  light.  The  rose  quartz  is  not  held  in  great  estimation ; 
the  color  as  well  as  the  lustre  of  faded  rose  quartz  may 
be  resuscitated  by  being  left  for  some  time  in  a  moist 
place. 

A  vase  of  rose  quartz  was  in  the  possession  of  the  Marquis 
de  Dree,  nine  inches  high  and  two  inches  in  diameter. 

Cat's-eye. 

The  name  of  this  mineral  is  derived  from  the  peculiar 
play  of  light  perceptible  on  its  surface,  by  which  it  resem- 
bles the  rays  of  light  in  the  eyes  of  a  cat ;  it  is  not  ascer- 
tained whether  the  ancients  knew  this  mineral,  and  whether 
it  was  comprised  in  their .asterias;  but  it  is  well  known  that 
cat's-eye  is  in  high  estimation  among  the  Malabars  and 
Moors ;  and  it  is  worn  throughout  the  whole  East,  where  it 
is  employed  as  an  amulet,  being  believed  to  possess  the  virtue 

of  enriching  the  wearer. 

• 

Cat's-eye  occurs  massive,  and  in  more  or  less  roundish 
pieces  ;  has  a.  conchoidal  fracture  ;  is  translucent  and  trans- 
parent sometimes  on  one  end ;  it  has  a  shining  lustre, 
between  vitreous  and  resinous ;  gray  and  brown,  green, 
red  and  yellow  color ;  it  presents  a  peculiar  floating  light, 
which  is  particularly  visible  if  cut  in  high  cabochon,  as  it 
usually  is  when  brought  to  market;  it  scratches  glass;  has 
a  specific  gravity  of  2'56  to  2'73,  and  contains  95  silex, 
1*75  alumina,  1'50  lime,  and  0*26  oxide  of  iron.  In  many 
specimens,  there  may  be  observed  small  parallel  white 
fibres,  which  are  supposed  to  be  the  cause  of  its  peculiar 
play  of  light ;  but  the  semi-transparent  varieties,  which 
are  equally  chatoyant  as  the  more  opaque  ones,  present 
no  such  appearance.  This  leads  to  the  conclusion  that 


COMMON    QUARTZ.  27l 

amianthus  in  its  finest  fibres  occasions  the  phenomenon, 
and  the  chemical  analysis  of  the  latter  corresponds  with 
the  additional  constituents  of  the  cat's-eye.  By  exposure 
to  a  strong  heat,  it  loses  its  lustre  and  transparency ;  and, 
in'  small  fragments,  is  fusible  before  the  blowpipe.  Cat's- 
eye  is  found  in  fragments  of  gangues  and  boulders,  of 
very  small  size,  never  larger  than  a  hazel-nut,  in  Ceylon, 
on  the  coast  of  Malabar,  in  the  Hartz  mountains,  Bavaria, 
and  in  this  country,  (in  Vermont,  New-York,  <fcc.)  Ceylon, 
where  the  finest  cat's-eyes  are  found,  sends  them  abroad 
already  cut  and  polished  in  cabochon ;  but  very  often  they 
are  cut  over  again  on  a  copper  wheel,  with  emery,  and 
polished  on  a  tin  plate ;  they  receive  in  setting  a  gold  foil. 
The  value  depends  principally  upon  its'  intrinsic  properties, 
size,  color,  and  degree  of  play  of  light.  Of  the  nearly 
opaque  varieties,  the  red  and  the  almost  white  are  the  most 
esteemed,  and  such  are  sold  usually  from  ten  to  twenty 
dollars ;  and  a  stone  of  the  size  of  a  square  inch,  and  other- 
wise perfect  in  its  properties,  is  worth  from  eighty  to  one 
hundred  dollars.  § 

In  the  imperial  cabinet  of  Vienna,  a  cat's-eye,  five  inches 
in  length,  of  a  yellowish-brown  color,  may  be  seen. 

The  Indians  attribute  to  cat's-eye  wonderful  virtues,  and 
the  largest  and  prettiest  stones  are  said  to  possess  them  in  a 
high  degree. 

Jean  Ribeiro  quotes,  in  his  "  History  of  Ceylon,"  a  cat's- 
eye,  belonging  to  the  Prince  of  Ura,  which  was  perfectly 
round  and  of  the  size  of  a  pigeon's  egg,  possessing  magnifi- 
cent chatoyant  colors ;  changing,  on  the  least  movement  of 
the  stone,  its  beautiful  reflections. 

Prase. 

This  mineral  is  mentioned  by  Pliny ;  but  it  is  not  cer- 
tain whether  he  meant  the  same  substance  that  we  do : 


272  A  POPULAR  TREATISE  ON  GEMS. 

more  probably  he  alluded  to  the  emerald ;  for  the  same  min- 
eral is  at  the  present  time  called  the  emerald  mother  or 
matrix  by  jewellers.  Prase  occurs  massive  and  crystallized; 
it  has  a  conchoidal  fracture  ;  is  translucent  on  the  edges ; 
between  vitreous  and  resinous  in  lustre  ;  and  of  a  garlic- 
green  color,  the  cause  of  which  is,  that  actinolite  is  inter- 
mixed with  the  silex.  It  scratches  glass  ;  has  a  specific  gravity 
of  2-66  to  2-88,  and  is  composed  of  silex,  alumina,  and 
oxides  of  iron  and  manganese.  It  is  found  in  Saxony,  Tyrol, 
Styria,  Hartz,  and  the  island  of  Elba.  It  is  used  for  rings 
and  pins ;  also  for  snuff-boxes  and  other  jewelry,  and  is  cut 
in  cabochon,  and  set  with  a  gold  foil  at  the  base,  by  which 
its  color  is  heightened,  and  rendered  more  agreeable.  It  is 
used  in  mosaic  works,  for  foliage ;  and  likewise  in  the 
mounting  of  rubies,  in  order  to  raise  their -color.  Prase  does 
not  stand  in  great  estimation ;  for  although  it  assumes  a  very 
good  polish,  it  loses  the  same  on  long  ^exposure  to  the  air, 
and  grows  spotty. 

Avanturine. 

This  mineral  received  its  name  from  bearing  a  resemblance 
to  a  glass  paste,  formerly  manufactured  in  Italy.  It  is  a 
brown  or  red  quartz,  which  is  massive  and  translucent,  or 
opaque ;  it  has  a  resinous  lustre,  and  its  fracture  is  splintry 
and  uneven  ;  it  is  penetrated  with  gold  or  brass-yellow  glis- 
tening fissures,  caused  by  the  refraction  of  light,  or  by  innu- 
merable mica  leaves.  It  scratches  white  glass  ;  has  a  specific 
gravity  of  2 '64  to  2 '68  ;  silex,  with  some  alumina  and  water, 
are  its  constituents. 

The  avanturine  is.  found  in  the  Uralian  mountains,  Styria, 
Cape  de  Gata,  near  Madrid,  Nantes,  Scotland,  &c.  It  is 
used  "for  ring-stones,  ear-rings,  and  snuff-boxes.  It  is  cut 
on  a  copper  wheel,  with  emery,  and  polished  with  rotten- 


JASPER.  273 

stone  on  a  tin  plate ;  it  is  cut  semi-lenticular  or  oval,  does 
not  take  easily  a  good  polish,  but  may  be  improved  by 
rubbing  the  stone  with  oil  of  almonds*  The  value  of  avan- 
turine  is  much  depreciated  of  late,  and  its  imitation  by  glass 
paste,  called  goldstone,  is  by  far  superior  to  the  real  stone, 
which  has  nothing  but  hardness  in  its  favor.  This  paste  is 
manufactured  in  great  quantities  in  France,  by  throwing  the 
finest  impalpable  powdered  brass  into  a  quantity  of  colorless 
strass,  or  into  a  composition  of 

105  parts  quartz, 
85     "       purified  potash, 

230     "       tin  and  lead  alloy> 

50     "       brass  powder. 

The  artificial  avanturine,  as  made  in  Italy,  is  a  silicious 
oxide  of  copper.  The  mode  of  manufacturing  the  best 
quality,  which  is  done  very  extensively  in  Italy  and  France, 
is  still  kept  a  secret ;  that  the  copper  is  reduced  first  to  a 
sub-oxide,  and  nearly  to  its  crystalline  metallic  state,  may 
be  inferred  on  examining  with  a  microscope  the  common 
artificial  stone,  which  has  a  most  splendid  appearance* 
The  best  ananturine  is  manufactured  in  Venice,  by  M.  P. 
Bibaglia,  who  alone  appears  to  have  the  secret  of  excelling 
the  natural  stone.  Messrs.  Fremy  and  Ckmendot,  expert 
French  chemists,  have  succeeded  in  approximating  the  Ve- 
netian manufacture,  by  heating  300  parts  ground  glass  with 
40  parts  of  protoxide  of  copper  and  80  parts  of  oxide  of 
iron,  and  allowing  the  mass  to  cool  very  slow. 

Large  blocks  of  the  factitious  avanturine,  with  a  great 
variety  of  manufactured  ornaments,  were  admired  in  the 
Paris  Exhibition,  in  1855. 

JASPER. 

This  mineral  is  of  Oriental  origin,  and  is  very  often  men- 
tioned in  the  Bible.  *  It  was  the  sixth  stone  in  the  plate  of 

12* 


274  A   POPULAR   TREATISE    ON    GEMS. 

the  high-priest.  Jasper  was  well  known  to  the  Greeks  and 
Romans,  and  according  to  Pliny,  who  has  described  sev- 
eral varieties,  the  best  came  from  Scythia,  Cypria,  and 
Egypt,  on  the  banks  of  the  Nile.  The  lapidaries  formerly 
made  use  of  it  in  their  works,  particularly  the  Egyptian 
jasper,  which  afforded  them  abundant  material.  The  col- 
umn of  Memnon  and  the  foundation  of  the  column  of  Pom- 
pey  were  constructed  of  it,  and  we  find  daily,  among  the 
excavations  of  Herculaneum  and  Pompeii,  fragments  of  ruins, 
composed  of  Egyptian  jasper. 

Jasper  occurs  in  enormous  masses ;  has  a  conchoidal  frac- 
ture ;  is  opaque ;  its  lustre  is  slightly  resinous,  like  wax, 
often  dull ;  it  is  of  white,  red,  yellow,  green,  blue,  brown  and 
black  colors ;  it  scratches  glass,  but  yields  to  rock  crystal  ; 
its  specific  gravity  is  2-31  to  2*67. 

It  is  usually  found  in  gangues,  seldom  in  strata,  in  Egypt, 
Bohemia,  Saxony,  Tyrol,  Hungary,  France,  Italy,  Spain, 
Siberia,  Corsica  ;  in  the  United  States,  principally  in 
Florida,  North  Carolina,  Massachusetts,  &c. ;  also,  in  Nova 
Scotia. 

A  fine  yellow  jasper  is  found  at  Vourla,  bay^of  Smyrna, 
in  a  low  ridge  of  limestone,  to  the  right  of  the  watering- 
place,  between  the  harbor  and  the  high  hills  that  commence 
their  rise  about  a  mile  back ;  it  is  here  associated  with  a 
beautiful  opal,  coarse  carnelians,  chrysoprase,  and  horn- 
stone,  and  these  minerals  seem  to  occupy  in  the  limestone 
the  place  of  the  hornstone,  which  is  found  in  various  parts  of 
the  adjoining  country,  and  also  at  Napoli  di  Romania,  in 
Greece.  The  plains  of  Argos  are  strewed  with  pebbles  of  red 
Jasper. 

The  jasper  and  quartz  rocks  of  Siberia  am  well  known 
materials  of  extreme  hardness,  worked  only  in  the  Russian 
empire,  and  are  rarely  met  with,  except  as  imperial  pres- 
ents to  princes  and  distinguished  foreigners.  A  group  of 


JASPER.  2*75 

very  remarkable  objects  was  exhibited  among  the  Russian 
goods  in  the  London  Exhibition.  The  material  of  some  of 
these  vases  is  quartz  rock,  but  most  are  of  a  kind  of  pseudo 
jasper  or  pseudo  jasper  lava,  of  greenish  color,  and  extreme 
toughness  and  hardness,  resisting  almost  every  tool,  and 
requiring  to  be  cut  with  emery,  like  the  hardest  gems. 
These  rocks  chiefly  exist  in  Siberia,  beyond  the  Oural,  and 
are  in  great  abundance  and  variety.  The  vases  of  jasper 
were  worked  at  the  imperial  manufactories  of  Ekaterinen- 
burg  and  Kolyvan.  There  almost  the  whole  work  is  per- 
formed by  manual  labor ;  the  only  machine  used  is  a  simple 
lathe,  on  which  the  object  to  be  turned  is  placed,  and 
worked  by  iron  tools  and  emery.  No  tool  will  touch  these 
stones,  both  chisels  and  files  of  the  hardest  temper  turning 
without  producing  any  effect.  The  time  'for  furnishing 
vases  of  considerable  magnitude  is  often  many  years,  and 
their  value  is  calculated  by  the  cost  of  the  large  establish- 
ment kept  at  constant  work.  A  large  vase,  measuring  three 
feet  on  each  side,  in  a  square  form,  was  exhibited,  hollow 
under  the  rim,  with  foliage  in  the  same,  and  was  one  of  the 
great  curiosities  in  the  Exhibition.  Smaller  vases,  an  olive- 
green  jasper  urn,  decorated' with  admirably  worked  foliage 
in  relief,  from  the  imperial  manufactories,  were  -likewise 
exhibited,  all  of  which  excited  the  admiration  of  the  specta- 
tors; and  since  the  times  of  the  Greeks  and  Romans  no  such 
gigantic  works,  both  in  dimensions  and  weight,  have  been 
wrought.  The  quantity  of  intaglios  and  cameos  from  the" 
ancient  Greeks  and  Romans  is  too  numerous  for  giving  them 
a  space  in  this  treatise,  for  it  would  fill  a  whole  book  to  spe- 
cify the  antiques  which  are  scattered  around  the  world,  in 
the  various  museums  of  Rome,  Vienna,  Paris,  London,  Ber- 
lin, Dresden,  and  the  private  cabinets  which  have  for  centu- 
ries existed  in  noble  families. 

According  to  their  varieties,  which  are  very  numerous — 


276  A   POPULAR   TREATISE    ON    GfEMS. 

that  is,  in  color  and  structure — they  receive  their  names  \ 
but  they  may  still  be  classified  into  the  following  two- 
divisions  : 

1.  Egyptian    Jasper,     (Egyptian    pebble,)   which    occurs- 
in  spheroidal   pieces,,  of  a  gray-brown    and  red   color,  the- 
form    of  which   is    cut   and   polished  in   annular   represen- 
tations   around    its   centre.      It   is   found   in   Baden,   tip- 
per  Egypt,   and  other   places ;    among  the  pebbles  of  the 
river   Nile  it  is  frequently    discovered  ;    and   in   the   year 
1714,    it  was   found  near  the  village   of  Inch  eric;  by  Paul 
Lucas. 

2.  Ribbon  or    Striped  Spar.     It    occurs  in   masses,  with 
nearly  conchoidal  fracture,  around  which  parallel,  straight,. 
or  twisted  stripes    of  a   gray,   green,  yellow,  red,  or  brown 
color  may  be   perceived  ;  it  is  principally  found  in  Siberia, 
the  East  Indies,  Corsica,  Tyrol,   and  the  Hartz  mountains ; 
some  of  the  West  India  islands  produce  most  splendid  spe- 
cimens. 

Jasper  is  principally  used  for  seals,  snuff-boxes,  vases, 
table-plates,  and  for  some  architectural  purposes. 

When  in  lumps,  it  is  divided  by  means  of  copper  saws 
and  fine  sand,  and  then  cut  on  copper  or  leaden  wheels 
with  emtfry,  and  polished  on  tin  plates  with  rotten  stone, 
colcothar,  or  charcoal ;  or  it  may  first  be  polished  on  wood 
with  pumice  stone,  and  lastly  on  a  tin  plate  with  rotten  stone 
and  water. 

The  yellow  jasper  is  often  employed  in  mosaic  works  in 
Italy,  and  the  striped  jasper  as  cameos.  Jasper-  has  no 
great  value  in  trad-e,  unless  it  be  of  exquisite  quality,  and 
fine  objects  be  made  of  it.  It  generally  commands  the 
best  price  in  China,  where  the  emperor  has  a.  seal  cut  of 
it.  A  vase  of  red  Jasper,  with  white  veins,  and  one  of 
black  jasper,  with  yellow  veins,  may  be  seen  in  the  Vati- 
can. Chatouilles  and  other  boxes  of  considerable  size 


CHALCEBONt, 


are  frequently  fotmd  in  the  jewelry  stores  of  France,  Eng- 
land,- and  the  United  States, 


HORNSTONE, 

Hornstone  occurs  massive,  globular,  stalactiform,  and  in 
pseudo-morphous  crystals  of  carbonate  of  lime,  and  also  in 
the  form  of  petrified  wood,  (wood-stone  or  agatized  wood.) 
Its  fracture  is  either  conchoidal  or  splintry ;  it  is  opaque  or 
transparent  on  the  edges;  has  a  dull  or  shining  lustre;- deep 
gray,  brown,  red,  yellow,  or  green,  and  rarely  a  pure  color. 
Often  it  has  several  colors  in  one  and  the  same  specimen, 
such  as  points,  spots,  and  stripes.  It  scratches  glass,  and 
has  a  specific  gravity  of  2 '53  to  2 '65. 

It  is  mostly  found  in  the  gangues  of  the  older  formation  J 
also  in  the  old  red  sandstones  and  alluvial  formations,  in 
Bohemia,  Saxony,  Sweden,  Siberia,  Hungary,  and  a  number 
of  other  places ;  in  the  old  red  sandstone  of  Thuringia.  I 
have  traced  one  stem  of  the  red  agatized  wood  eighteen  feet 
in  length  and  two  feet  in  diameter.  The  price  of  hornstone 
is  very  low  ;  it  is  used  for  snuff-boxes,  seals,  crosses,  mortars, 
and  principally  as  knife  and  fork  handles.  It  is  now  used 
by  silversmiths  to  mount  butter  and  dessert  knives  and  forks," 
which  are  imported  from  Germany  in  considerable  quan- 
tities-. 

CHALCEDONY. 

This  mineral  was  held  in  great  estimation  by  the  ancients, 
who  received  their  principal  supplies  from  Egypt  and  other 
parts  of  Africa.  In  Rome,  much  use  was  made  of  it  for 
cameos,  many  of  which  may  yet  be  seen  in  collections.  The 
inhabitants  of  Iceland  are  likewise  said  to  value  it  very 
highly,  and  to  attribute  many  medicinal  properties  to  it* 


278  A  POPULAR  TREATISE  ON  GEMS. 

It  is  found  in  crystals,  such  as  cubes,  but  mostly  massive, 
botryoidal,  stalactiform,  globular,  or  reniform,  &c.  The 
fracture  is  even,  sometimes  running  into  conchoidal  or 
splintry ;  it  is  semi-transparent  or  translucent,  of  little 
lustre,  or  dull ;  of  white,  gray,  blue,  yellow,  brown  or  green 
colors,  which  are  all  of  a  light  shade,  and  variously  figured, 
striped,  spotted,  &c. 

It  scratches  white  glass,  and  has  a  specific  gravity  of 
2'58  to  2*66.  It  is  distinguished  into  the  following  varieties, 
viz. : 

1.  Chalcedony  proper,  or  chalcedony x,  wherein  white  and 
gray  stripes  alternate  with  each  other. 

2.  Mocha,  or  tree  stones,  are  such  chalcedonies  as  display 
black,  brown,  or  red  dendritical  figures, 

3.  Rainbow,  or  agate  chalcedony,  is  chalcedony  of  thin 
and  concentric  structure,  which,  cut  across  and  kept  towards 
the  light,  displays  an  iridescence. 

4.  Cloudy  chalcedony,  has  a  light  gray   and   transparent 
base,  with  dark  and  cloudy  spots. 

5.  Plasma,  dark  grass-green.     This  mineral  was  very  often 
employed  by  the  ancients  for  cutting. 

6.  Semi-carnelian,  or  ceregat,  is  generally  called  the  yellow 
chalcedony. 

7.  Sappharine,  is  the  sky  or  sapphire  blue  chalcedony. 

8.  St.   Stephen's  stones,  is  the    white    chalcedony,  with 
blood-red  spots. 

There  are  many  more  varieties,  and  in  my  own  collection 
I  have  polished  chalcedonies,  among  which,  perhaps,  as  many 
again  may  be  enumerated. 

Chalcedony  was  originally  procured  from  Chalcedon,  in 
Asia  Minor,  whence  its  name. 

Chalcedony  is  found  in  gangues,  and  in  the  cavities  of 
many  rocks  ;  also  in  boulders  and  pebbles.  Localities  exist 
in  Saxony,  Hungary,  Faroe  Islands,  Ceylon',  on  the  shores 


279 

of  the  Nile,  in  Nubia,  Nova  Scotia,  the  UnUed  States,  (in 
Connecticut,  Massachusetts,  Pennsylvania,  Ohio,  New-Jersey,. 
Missouri,  Florida,)  and  in  other  countries;  but  the  best 
specimens  are  brought  from  Oberstein,  Iceland,  and  the 
Faroe  Islands. 

The  finest  specimens  are  employed  in  jewelry,  for  rings, 
pins,  bracelets,  necklaces,  and  seals; -the  more  common  for 
snuff-boxes,  vases,  buttons,  &c.  The  larger  masses  are  cut 
by  means  of  a  copper  wire,  with  emery  and  oil  on  a  copper 
wheel ;  they  are  polished  on  a  tin  plate  with  rotten  stone, 
putty-powder,  and  pumice  stone.  The  cutting  is  generally 
done  on  a  large  scale,  like  that  of  agate.  Many  are  suscepti- 
ble of  receiving  figures  artificially,  by  means  of  the  nitrate  of 
silver.  By  Oriental  chalcedony  is  generally  understood  the 
better  qualities  ;  those  chalcedonies  of  two  or  three  divisions, 
called  onyx,  are  used  for  cameos. 

The  value  of  the  chalcedony  depends  on  its  quality,  such 
as  purity,  color,  and  the  figures  and  drawings  displayed  on 
it ;  and  among  all  the  varieties  of  chalcedony,  the  mocha 
stone  stands  the  highest  in  price,  and  also  the  onyx,  which 
is  principally  employed  for  cutting  cameos,  and  according 
to  its  size,  commands  a  high  or  low  price.  Mocha  stones 
are  sold  in  France  at  from  five  to  eight  francs.  The  cabi- 
net of  Dresden  contains  a  plate  of  onyx,  about  three  inches 
broad  and  long,  which  is  estimated  at  twenty-five  thousand 
dollars. 

CARNELIAff. 

This  stone  was  known  to  the  ancients  by  the  name  of  Sarda ; 
which,  according  to  some,  is  derived  from  a  place  in  Lybia 
or  Sardinia,  or,  according  to  others,  from  the  Arabic  word 
sarda,  meaning  yellow;  it  has  been  employed  very  frequently 
for  cutting  intaglios  or  bas-relief  gems. 

Carnelian  occurs  massive  or  in  pebbles ;  its  fracture  is  con- 


280  A    POPULAR   TREATISE    ON 

choidal ;  lustre  resinous ;  it  is  semi-transparent  and  translu- 
cent; of  a  blood-red,  yellow-brown,  or  yellow  color;  fre* 
quently  dark  at  the  outside*  growing  paler  towards  the  in- 
side ;  the  colors  are  sometimes  changing  striated ;-  it  scratches 
white  glass,  and  has  a  specific  gravity  of  2-59  to  2 '63.  There 
are  two  varieties  known  by  lapidaries  and  jewellers  which 
are  better  than  the  others;  those  having  a  pale  color  or  yel- 
lowish tinge,  and  those  having  a  dark-red  color;  the  latter 
are  in  the  highest  estimation,  and  are  called  by  the  French 
cornalines  de  vieille  roche. 

Sardonyx  is  called  a  carnelian,  having  as  its  principal  color 
tne  dark-brown  or  orange-yellow,  interchanged  with  layers 
of  a  white  color. 

Carnelian  onyx  has  a  blood-red  base,  marked  with  white 
stripes.  The  finest  carnelians  come  from  Siberia,  India, 
Arabia,  Nubia,  Surinam,  Oberstein  in  Germany,  and  Tyrol ; 
they  occur  mostly  as  pebbles  or  in  .cavities  of^  rocks.  In  the 
United  States  they  are  found  on  Lake  Superior  in  large 
quantities,  in  Missouri,  and  in  Massachusetts.  The  carne- 
lian is  used  for  numerous  articles  in  jewelry,  such  as  seals, 
rings,  watch-keys,  &c. ;  it  is  cut  on  a  leaden  plate  with 
emery,  and  is  polished  on  wood  with  pumice  stone,  and  ob- 
tains its  highest  polish  on  a  plate  composed  of  lead  and  tin 
with  rotten  stone  and  water.  The  form  of  its  cutting  is 
that  of  pavilion  or  step  cut,  on  the  upper  part,  and  either 
quadrangular,  hexagonal,  octangular,  or  round ;  and  for 
raising  its  lustre  or  color  it  is  furnished  with  a,  silver  or 
gold  foil,  or  with  red  paint  on  its  base.  The  color  of  th£ 
carnelian  is  also  improved  by  calcination ;  the  yellowish 
kind,  for  instance,  by  calcining  it  in  a  moderate  heat  and 
cooling.it  slowly,  may  assume  a  good  red  color.  It  is  said 
that  the  ancients  boiled  the  carnelian  in  honey  in  order  to 
heighten  its- color.  Colored  figures  or  drawings  may  suc- 
cessfully be  represented  by  a  mixture  of  white-lead,  colco- 


CARNELIAN.  281 

thar,  or  other  metallic  oxides,  and  gum-water,  which  is  the 
material  for  drawing  on  it,  and  by  burning  the  same  under  a 
muffle. 

Carnelian  is  divided  into  Oriental  and  occidental ;  the  first 
is  found  in  the  old  rocks,  and  is  generally  very  hard,  rich  in 
color,  clear  and  transparent,  and  takes  a  high  polish,  is 
brought  from  Surat,  in  the  Indies,  and  valued  at  ten  francs  the 
kilogramme  ;  the  occidental  carnelian  is  softer,  of  a  yellower 
red  and  less  brilliant. 

Stygmite  is  a  beautiful  variety  with  variegated  colors,  of 
reddish-yellow  or  yellowish-red,  with  many  white  lines  pass- 
ing through  the  stones. 

The  ancients,  particularly  the  Romans,  were  very  partial 
to  engraving  on  carnelian,  and  some  very  remarkable  stones 
are  still  in  existence  in  the  imperial  library  at  Paris.  The 
seal  of  Michael  Angelo,  which  is  valued  at  50,000  francs, 
is  said  to  have  been  engraved  by  Maria  de  Descias  after 
the  original  of  Praxiteles ;  the  bust  of  Ulysses,  Hercules 
killing  Diomede,  Jupiter,  Mars,  and  Mercury. 

The  great  scarabee  in  carnelian,  in  the  Prussian  cabinet, 
which  represents  the  five  heroes  of  Thebes,  is  a  master-piece 
of  Etruscan  art. 

The  crown  jewels  of  France  contain  some  very  costly  car- 
nelian engravings  of  very  large  size. 

The  faults  of  the  carnelian  are  fissures,  unequal  color,  and 
flaws  from  other  stones.  Carnelian  is,  on  account  of  its 
being  less  brittle,  more  useful  for  engraving  and  cutting 
cameos ;  the  white  layers  are  generally  used  for  the  figures 
of  cameos  and'  the  red  for  the  base.  Sometimes  such 
carnelians  as  are  cut  with  bas-relief  objects,  are  filled  out 
with  colored  strass ;  and  we  receive  from  India,  very  fre- 
quently, cameos  with  the  most  singular  drawings,  and  which 
are  made  by  the  inhabitants  in  the  following  manner :  the 
whole  carnelian  is  covered  with  carbonate  of  soda,  and  then 


282  A    POPULAR   TREATISE    ON    GEMS. 

exposed  to  the  fire  for  a  few  minutes,  whereby  a  strass  is 
formed,  upon  which  the  figures  are  cut.  The  value  of  car- 
nelian  is  much  higher  than  chalcedony,  but  yet  depends  on 
all  its  qualities  of  color,  transparency,  equal  division  of  color, 
and  freedom  from  faults,  such  as  fissures,  clouds,  dark  spots, 
&c.  For  a  perfect  sardonix,  a  very  high  price  is  generally 
given,  particularly  when  the  layers  are  very  distinct  and 
run  quite  parallel,  and  are  pretty  thick,  so  that  they  are 
fit  for  cutting  cameos  or  intaglios.  The  blood-red  is  second 
in  value,  and  the  pale-red  third ;  but  the  cheapest  are  the 
yellowish,  brownish,  or  whitish  kinds  ;  the  prices  vary  from 
twenty  dollars  to  twenty  cents  per  piece.  There  exists  a 
cameo  of  sardonyx,  representing  the  portrait  of  the  celebrated 
Father  Fontanarosa,  having  his  face  white,  with  the  base, 
cap,  and  cloak  black,  so  that  it  may  distinctly  show  the 
Dominican  monk. 


HELIOTROPE,  BLOODSTONE. 

This  stone  derives  its  name  from  the  Greek  language, 
having  been  used  in  ancient  times  for  observing  the  sun. 
Pliny  speaks  of  heliotrope.  It  occurs  in  massive  and 
obtuse  angular  lumps,  of  a  conchoidal  fracture,  is  trans- 
lucent on  the  edges,  of  a  resinous  lustre,  and  leek-green 
color,  with  red  and  yellow  spots.  It  scratches  white  glass  ; 
has  a  specific  gravity  of  2*61  to  2'63.  Heliotrope  is 
found  among  amygdaloid,  in  Tyrol,  in  the  United  States, 
(in  New-York,  near  Troy,)  Scottish  Islands,  Siberia,  Faroe 
Islands,  Egypt,  Barbary,  Tartary,  &c.  It  is  principally 
employed  in  rings  and  seals,  watch-keys,  snuff-boxes,  and 
other  articles  of  jewelry, — also  for  sword  and  dagger  han- 
dles ;  and  is  wrought  like  chalcedony,  but  sometimes  cut 
on  brass  plates ;  its  forms  are  various :  as  cabochon  and 
pavilion. 


AGATE.  283 

Heliotrope  has  been  greatly  admired  in  modern  times ; 
its  pric'e  depends  upon  the  color  and  quantity  of  red  spots 
contained  in  ft.  From  one  to  twenty  dollars  is  the  usual 
price  for  good  and  large  specimens. 

It  is  said  that  superstitious  people  in  the  middle  ages 
valued  the  heliotrope,  with  many  red  spots,  very  highly, 
thinking  that  Christ's  blood  was  diffused  through  the  stone. 


AGATE. 

This  stone  was  well  known  to  the  ancients,  under  the 
name  of  achates,  and  was  used  for  various  purposes  of  jew- 
elry. In  Rome,  it  was  principally  used  for  cutting  cameos 
from  the  striped  kind,  the  onyx.  It  has  also  been  worn  as 
an  amulet,  with  different  characters  engraved  upon  it.  Its 
name  is  derived  from  a  river  in  Sicily,  where  the  ancients 
procured  it.  Agate  is  a  mixture  of  several  species  of  quartz, 
which  are  variously  combined ;  chalcedony  or  carnelian 
usually  forms  the  principal  part,  and  is  mixed  with  horn- 
stone,  jasper,  amethyst,  quartz,  heliotrope,  cachelong,  and 
flint;  and  according  to  the  predominating  substances,  it  is 
sometimes  called  chalcedony,  jasper,  or  carnelian  agate.  Its 
color,  as  well  as  its  other  characters,  depends  upon  the  na- 
ture of  the  mixed  parts  ;  likewise  its  hardness  ;  but  it  usually 
scratches  white  glass,  and  has  a  specific  gravity  of  2*58  to 
2-66  at  the  utmost. 

According  to  the  different  figures  represented  in  agate,  it 
receives  its  various  names. 

1st.  Ribbon,  or  striped  agate,  representing  layers  vari- 
ously colored,  and  alternating  with  one  another.  Onyx, 
or  agate  onyx,  are  such  agates  as  have  the  colors  beautiful 
and  distinct,  and  whose  layers  run  in  a  parallel  direction 
with  the  larger  surface ;  whereas  the  common  ribbon  agates 
display  their  various  layers  on  the  surface,  without  being 


284  A    POPULAR   TREATISE    ON    GEMS. 

parallel.  If  the  stripes  run  together  around  the  centre,  it 
is  called  the  circle  agate,  and  if  in  the  same  stone  the 
centre  shows  more  colored  spots,  it  is  called  the  eye  agate, 
or  eyes  tone. 

2d.  Fortification  agate  is  that  brownish  agate,  the  vari- 
ous colored  stripes  of  which  run  in  a  zig-zag,  or  irregular 
lines  and  angles,  representing  the  ground  plan  of  fortifica- 
tions. 

3d.  Rainbow  agate ;  the  curved  stripes  have  the  property 
of  displaying  rainbow  colors  when  held  towards  the  sun, 
or  candle-light,  and  the  more  distinctly  if  the  stone  is  cut 
very  thin. 

4th.  The  cloud,  landscape,  dendritic,  figure,  moss,  punc- 
tated, star,  petrifaction,  shell,  coral,  tube,  fragment,  and  ruin 
agates  are  all  the  various  forms  in  -which  the  agate  is  dis- 
played, according  to  its  figure  or  drawing.  A  ruin  or  frag- 
ment agate  may  be  pasted  together  from  the  fragments  of 
a  common  ribbon  agate,  so  as  to  make  it  represent  old 
walls,  whereby  it  receives  the  name  of  breccia  agate  ;  some- 
times the  rainbow  agate  occurs  in  connection  with  the  shell 
agate,  where  the  moss  surrounding  the  petrified  shells  forms 
the  rainbow  agate. 

The  royal  collection  at  Dresden  contains  a  table  service  of 
German  agate;  at  Vienna,  in  the  imperial  cabinet,  there  .is 
an  oval  dish  twenty-two  inches  in  length,  formed  from  a  sin- 
gle stone. 

The  achates  of  the  Greeks  were  so  called  from  the  river 
Achates,  in  Sicily,  whence,  according  .to  Theophrastus,  these 
stones  were  originally  brought. 

J  asp  achates  corresponds  to  our  jasper  agate  ;  sardachates 
contained  layers  of  the  sarda,  or  carnelian  ;  dendrachtes, 
from  &evtpov,  a  tree,  corresponding  to  our  moss  agate ; 
hsemachates,  from  d^a,  blood,  which  was  an  agate  sprinkled 
with  spots  of  red  jasper. 


AGATE.  285 

Among  the  crown-jewels  of  France,  is  a  very  valuable  set 
>f  agates, — ten  cups  and  sa.ucers,  four  urns,  four  chandeliers, 
four  busts,  two  ewers,  two  basins,  two  vases,  two  bowls,  two 
salvers,  one  decanter,  and  one  candlestick ;  the  whole  set  is 
valued  at  500,000  francs. 

At  the  French  Exhibition  in  1855,  a  magnificent  Oriental 
agate,  by  Froraent  Maurice,  belonging  to  the  Princess 
Mathilde,  was  exhibited,  having  the  engravings  of  the 
three  infatuations,— the  amorous,  the  poetical  and  sad,  most 
tastefully  represented.  It  is  the  Benvenuto  Cellini  of  our 
day. 

The  most  celebrated  cameo  in  Oriental  agate,  is  the  bust 
of  Alexander  the  Great,  which  is  a  perfect  gem ;  the  head  is 
quite  independent  in  color  froin  the  base  of  the  stone,  and 
the  execution  without  a  blemish. 

The  Orleans  collection  contained  two  agates :  one  repre- 
senting the  death,  of  Cleopatra,  as  a  half-body ;  the  other, 
Lysimachus,  the  head  girdled  with  a  diadem. 

A  large  black  agate,  particularly  remarkable  for  its  perfec- 
tion and  .the  complication  of  its  workmanship,  repre- 
sented a  captive  followed  by  two  generals  on  horseback,  and 
several  other  persons,  one  showing  a  trophy,  and  another  a 
laurel  branch, 

An  intaglio  of  Neptune,  belonging  to  the  Sabatini  Museum, 
was  also  exhibited. 

Agate  is  found  in  gangues,  in  gneiss,  porphyry,  or  amyg- 
daloid ;  also,  as  boulders  and  pebbles,  in  rivers,  &c.  It 
is  found  in  Baden,  Oberstein,  Saxony,  Bohemia,  Hungary, 
the  Faroe  Islands,  Siberia,  the  West  Indies,  and  in  the 
United  States,  (Massachusetts,  Rhode  Island,  New  Jersey, 
Indiana,  Missouri,  Maryland,  Georgia.)  Those  occurring- in 
amygdaloid  are  mostly  in  the  form  of  geodes,  or  balls, 
hollow  inside,  and  coated  with  quartz  or  amethyst ;  when 
the  rock  begins  to  disintegrate,  these  balls,  becoming 


286  A    POPULAR    TREATISE    ON    GEMS. 

loose ,  fall  scattering  around  the  soil,  and  are  then  collected 
by  persons  who  make  a  business  of  either  selling  or  cutting* 
them. 

The  agate  is  used  not  only  for  various  purposes  of 
jewelry  and  ornaments,  such  as  seals,  snuff-boxes,  crosses, 
cases  of  various  descriptions,  ear-drops,  &c.,  but  also  for 
numerous  other  useful  purposes,  on  a  large  scale ;  such  as 
slabs,  mortars,  vases,  instruments,  knife  and  fork  handles, 
playballs,  &c.  The  manufacturing  of  th^m  forms  a  con- 
siderable branch  of  industry  in  a  part  of  Germany.  The 
agate,  after  having  been  reduced  to  suitable  sized  pieces, 
by  means  of  a  saw,  chisel  or  hammer,  is  then  cut  on  a 
copper  wheel  by  means  of  emery,  powdered  garnet  or  topaz, 
and  is  afterwards  polished  on  a  tin  plate  with  rotten  stone, 
putty  or  pumice  stone. 

Oberstein,  a  small  place  in 'Rhenish  Bavaria,  in  the  north 
of  Germany,  has  five  large  manufacturing  establishments 
for  the  sole  purpose  of  cutting  and  polishing  the  common 
gems  or  semi-precious  stones,  and  it  is  the  only  place  where 
this  branch  of  business  is  carried  to  any  great  extent. 
Twenty  mills  are  constantly  driven  by  water,  and  more 
than  one  hundred  thousand  dollars  worth  of  work  is  turned 
out  yearly  for  export ;  a  sum  which  is  small  in  comparison 
with  the  enormous  quantity  of  goods  manufactured  and  set 
afloat,  but  pretty  considerable  for  such  places,  where  labor 
is  so  cheap,  and  the  best  of  workmen  may  be  had  for  one 
dollar  and  fifty  cents  per  week.  At  Oberstein  the  business 
is  divided  into  two  branches;  the  one  is  devoted  to  the 
cutting  and  polishing  of  the  agate,  and  the  other  to  the 
boring ;  the  workmen  are  called  agate  lapidaries  and  agate 
borers.  The  cutting  is  performed  in  the  large  agate 
mills,  on  sandstone  ;  each  mill  has  generally  five  large 
sandstones,  five  feet  in  diameter  and  fourteen  to  fifteen 
inches  in  thickness,  fastened  upon  a  shaft,  ^which  causes 


AGATE.  287 

them  to  revolve  vertically,  and  which  are  continually 
moistened  by  a  stream  of  water.  The  workman  leans  with 
his.  body  upon  a  peculiar  bench,  the  seat  of  which  is  called 
the  cuirass,  and  with  his  feet  presses  himself  against  a  pole, 
whence  he  continually  pushes  the  larger  lumps  of  the  agate 
towards  the  rnill-stotoe ;  this,  however,  is  often  made  so 
smooth  from  the  friction,  that  it  is  often  necessary  to  make 
it  rough  by  knocking  it  with  a  sharp  hammer,  according  to 
the  kind  of  work,  whether  fine  or  coarse.  The  stones  are 
either  polished  on  sandstone  or  on  wood,  by  means  of  fine 
clay  or  powdered  chalk ;  they  are  polished  sometimes,  also, 
on  wooden  wheels,  covered  with  lead  or  tin.  Snuff-boxes 
and  other  articles  of  agate,  which  are  hollow,  are  polished 
on  smaller  sandstone  wheels,  which  dimmish  in  size  as  the 
work  advances.  Agates  which  require  to  be  bored  belong 
to  a  particular  branch,  distinct  from  the  other.  The  boring 
is  performed  by  means  of  a  diamond  point,  and  is  described 
by  Mr.  Mawe.  The  onyx  varieties  are  mostly  employed 
for  cutting  cameos,  and  are  prepared  there  in  such  a  manner 
that  the  darker  layer  is  cut  for  the  base,  and  the  lighter  for 
the  intended  objects. 

There  is  in  Siberia,  at  Katherineburgh,  an  extensive 
manufactory  for  grinding  and  polishing  agate  and  other 
gems. 

Many  varieties  of  agate  are  used  for  engraving  other 
stones,  and  also  for  the  Florentine  or  stone  mosaic  work. 
Since  agate  has  always  been,  and  is  yet,  a  favorite. stone, 
it  has  been  attempted  to  improve  either  its  color  or  other 
"external  appearance  by  artificial  or  mechanical  means ;  this 
is  done  either  by  the  use  of  metallic  solutions  or  by  boiling 
in  oil  of  vitriol.  The  color  has  often  been  improved  by 
giving  to  the  stone,  before  it  is  polished,  several  strokes  in 
succession,  the  small  fissures  thereby  produced  displaying 
an  iridescence  or  some  other  phenomenon,  if  held  towards 


288  A     POPULAR   TREATISE    ON    GEMS. 

the  light  5  this  operation,  liowev.er,  may  easily  be  detected 
by  wetting  the  stone,  when  the  water,  entering  the  fissures, 
will  destroy  the  effect;  it  will  show  itself  again  when  dry. 
On  some  agates  black  and  white  layers  are  produced,  in 
order  to  use  or  sell  them  in  the  place  of  real  onyx ;  this 
operation  is  performed  by  the  lapidaries,  who  boil  certain 
varieties  in  oil  of  vitriol,  which  changes  the  color  of  some 
very  soon  to  black,  and  renders  others  clear  or  still  paler. 
Only  polished  agates  are  used  for  this  purpose,  and  the  cause 
appears  to  lie  in  the  oil  absorbed  by  them  during  the  opera- 
tion of  polishing,  on  which  account  agates  are  by  some  first 
boiled  in  oil  before  submitting  them  to  the  operation  of  the 
oil  of  vitriol. 

The  value  of  agate,  although  much  reduced  in  com- 
parison to  former  days, — a  great  deal  depending  upon  the 
purity  and  perfection  of  color  and  peculiar  figures, — com- 
mands a  pretty  good  price  in  the  market ;  it  is  particularly 
the  onyx  which  is  yet  at  high  prices,  and  on  that  account  it 
is  imitated  by  pasting  thin  plates  of  chalcedony,  jasper,  agate, 
&c.,  together,  and  making  them,  by  their  different  colors, 
appear  like  real  onyx ;  this  deception  may,  however,  be  easily 
detected  by  putting  it  into  hot  water,  which  disengages  the 
plates  one  from  another ;  the  onyx  is  likewise  imitated  by 
pastes,  and  very  happily,  but  may  readily  be  distinguished 
from  them  by  the  hardness  and  other  characters  prominent 
in  the  real  stones. 

Onyx,  which,  as  already  stated,  is  a  .variety  of  agate, 
and  most  frequently  of  chalcedony,  possesses  in  its  in- 
trinsic characters  a-  regular  alternation  of  layers,  which  are 
more  or  less  thick,  and  of  distinct  different  colors,  usually 
the  grayish  white,  brown,  and  black  predominating ;  while 
sardonyx  indicates  one  layer  or  more  to  be  of  carne- 
lian,  and  this  is  in  higher  estimation.  It  was  this  stone  par- 
ticularly which  the  ancients  mostly  sought  after  for  engrav- 


AGATE.  289 

ing  the  heads  of  celebrated  persons,  their  deities,  and  their 
idols;  the  fawn-colored  variety,  which  is  neither  yellow 
nor  red,  was  the  highest  in  value.  Both  onyx  and  sar- 
donyx were  purchased  in  Arabia  and  the  Indies,  and  the 
harder  the  stones  and  finer  the  grain,  the  more  valuable 
they  were  for  the  purpose  of  cutting.  The  title  of  Oriental 
onyx  was  always  given  to  »the  finest  qualities  of  the 
stones,  regardless  of  the  locality  from  whence  they  were 
brtmght. 

The  Imperial  Library  at  Paris  possesses  some  of  the  most 
antique  cameos  and  intaglios  of  onyx,  such  as  Germani- 
cus,  Marcus  Aurelius,  Faustina,  and  Tiberius ;  the  dread- 
ful Jupiter  is  an  onyx  in  two  layers ;  Venus  on  a  marine- 
bull,  surrounded  by  cupids,  are  personifications  of  the 
highest  perfection  in  the  art. 

The  superb  fragment  existing  in  Rome,  and  representing 
Antilochus  announcing  to  Achilles  the  death  of  Patrocles,  is 
another  master-piece ;  the  cameo  has  a*  black  ground,  with 
a  white  layer  above,  and  the  expression  of  grief  on  the 
three  faces  has  secured  to  this  cameo  the  decided  suprem- 
acy of  the  ancient  over  the  modern  art. 

The  bowl  of  Capo  di  Monte,  in  the  Royal  Museum  of 
Naples,  and  the  great  cameo  of  Alexander  and  Olympia, 
belong  to  Mr.  Bracciano,  at  Naples. 

The  French  Museum  contained  the  great  cameo  of  An- 
tonius  and  Faustina,  engraved  in  different  colors,  but  not 
parallel  lines,  it  is  not  inferior  to  any  other :  the  ground, 
which  is  of  agate  of  brownish  color,  is  Antonius,  and 
above,  in  a  white  layer,  is  the  pleasant  figure  of  Faus- 
tina, whose  drapery  and  hair  ornaments  are  exceedingly 
well  executed  in  a  lilac  color. 

The  sardonyx  is  also  called  sarde,  and  if  of  a  dark  sable 
color,  was  preferred  by  the  ancients  for  cutting  intaglios. 

Mars  and  Venus  when  surprised  by  the  gods,  is  executed 
13 


290  A   POPULAR   TREATISE   ON   GEMS. 

by  Valerio  Yicentine;  it  represented  nine  figures.  The 
Nuptials  of  Cupid  and  Psyche  contains  .five  figures. 

In  the  inventory  of  curiosities  belonging  to  the  crown  of 
France,  made  in  1*791,  are  mentioned  two  vases  of  sardonyx, 
valued  at  sixty-four  thousand  francs ;  six  sets,  at  one 
hundred  and  sixty-seven  thousand  francs ;  two  cups  at  six- 
teen hundred  francs;  one  decanter  at  thirteen  hundred 
francs ;  one  urn  at  six  hundred  francs ;  but  one  remarkable 
sardonyx,  of  a  grayish  yellow  mixed  with  brown,  on  which 
a  Medusa  head  was  engraved,  was  valued  at  twelve  thou- 
sand francs. 

The  onicolo  or  nicolo  is  another  variety  of  onyx ;  it  is 
of  brown  ground  with  a  band  of  bluish  white ;  it  is  distin- 
guished from  onyx,  by  the  lower  layer  being  always  thin- 
ner than  the  upper ;  it  is  not  so  highly  valued  as  either  the 
onyx  or  sardonyx.  The  Mineralogical  Cabinet  at  Paris 
possesses  several  cameos  of  this  material ;  one  represents 
military  piety ;  also  a  cameo  of  Adonis,  by  Coinus.  The 
stone  is  probably  the  cegyptilla,  described  by  Pliny. 

The  real  sardonyx  is  the  rarest  mineral  among  that  class 
of  stones,  on  account  of  the  multiplicity  of  layers,  of  which 
there  are  as  many  as  ten,  all,  however,  from  the  same  sub- 
stances, but  differently  colored :  such  as  chalcedony,  jasper, 
agate,  white,  gray,  red,  and  brown,  opaque,  translucent, 
bluish,  or  yellowish;  they  are  highly  prized,  particularly 
those  from  the  Orient. 

The  finest  cameo  of  the  real  Oriental  sardonyx  is  in  the 
imperial  cabinet  of  Vienna,  it  is  said  to  come  from  Diosco- 
rides ;  it  was  obtained  by  Rudolph  II.,  the  German  emperor, 
for  12,0(70  ducats. 

In  the  crown-jewels  of  France  are  some  unique  cameos 
of  sardonyx,  such  as  the  triumph  of  Bacchus  and  Ariadne, 
valued  at  7000  francs,  and  eleven  other  cut  stones  valued 
together  at  60,000  francs. 


AGATE.  291 

Great  collections  of  antique  onyxes,  engraved  as  cameos 
and  intaglios,  are  in  Vienna  and  Berlin;  in  the  first  is  to 
be  seen  the  apotheosis  of  Augustus,  which  is  ten  lines  broad 
and  six  high,  and  contains  twenty  perfect  figures ;  this  was 
purchased  by  the  Emperor  Rudolph  at  Frankfort-oir-the- 
Maine,  for  fifteen  thousand  ducats. 

The  celebrated  cameo  in  the  Vatican  Museum,  at'  Rome, 
is  of  agate,  and  represents  Augustus.  Italy  has  always  been 
the  great  emporium  for  genuine  antique  onyxes  and  cameos, 
and  occasionally  we  still  behold  fine  specimens  of  art  in  the 
.  possession  of  travellers  coming  from  Europe.  A  very  fine 
collection  of  antique  cameos  and  intaglios  in  precious  gems 
and  antique  pastes,  likewise  cameos  and  intaglios  of  modern 
artists,  I  have  seen  in  this  country,  in  the  possession  of 
Thomas  G.  Clemson,  Esq.,  of  Philadelphia. 

I  have  in  my  collection  a  good  onyx  of  the  Emperor  Vi- 
tellius ;  a  splendid  cameo  of  Bacchus,  of  two  and  one  fourth 
inches  long  and  one  half  inch  thick ;  one  of  Antony  and 
Cleopatra ;  also  a  splendid  intaglio. 

In  Paris  are  several  celebrated  cameos,  worthy  the  notice 
of  travellers  going  to  Europe :  the  Brunswick  Vase  was  cut 
from  a  single  stone,  and  has  the  form  of  a  cream  pot,  about 
Iseven  inches  high  and  two  and  a  half  broad  on  its  outside, 
which  is  of  a  brown  color;  there  are  white  and  yellow 
groups  of  raised  figures,  representing  Ceres  and  Triptole- 
mus  in  search  of  Proserpine;  Agrippina  and- her  two  chil- 
dren, composed  of  two  layers,  brown  and  white ;  the  Quar- 
rel of  Minerva  with  Neptune,  which  consists  of  three  layers ; 
Venus  on  a  sea-horse,  surrounded  with  cupids,  &c. 

The  Museo  Borbonico  at  Naples  contains  an  onyx  meas- 
uring eleven  inches  by  nine — the  apotheosis  of  Ptolemy  on 
one  side,  and  the  head  of  Medusa  on  the  other ;  both  are 
splendid  specimens  of  art,  and  supposed  to  be  the  largest  in 
existence. 


292  A  POPULAR  TKEATISE  ON  GEMS. 

Two  very  beautiful  flower-vases  of  black  onyx,  colored 
with  natural  white  veins,  two  large  cups  of  red  chalcedony 
colored,  long  square  links  of  chalcedony,  connected  together 
without  joints,  and  alternating  in  colors,  also  a  very  beau- 
tiful snuff-box  of  green  jasper,  were  seen  at  the  London 
Exhibition,  manufactured  by  Wild  &  Robinson,  in  Oberstein. 

Some  modern  works  of  cameo,  from  the  hand  of  the  cele- 
brated Puckler,  are  in  the  collection  of  Robert  Gilmore, 
Esq.,  at  Baltimore,  and  in  that  of  W.  J.  Lane,  Esq.,  of  this 
city,  who  possesses  also  a  Washington  head  of  black  and 
white  onyx,  by  Isler,  which  is  extremely  beautiful;  also  as 
very  fine  modern  cameo  in  onyx,  two  inches  in  length,  I 
saw  in  Stephen  H.  Palmer's  establishment. 

CHRYSOPRASE. 

The  ancients  by  this  name  designated  a  stone  of  a  green 
color,  with  a  yellowish  tinge ;  but  it  is  not  certain  whether 
that  which  goes  by  this  name,  at  the  present  day,  is  the 
same.  We  find,  in  the  fourteenth  century,  this  stone  used 
as  ornaments  in  churches  and  other  places,  but  it  was  not 
known  by  the  above  name  until  1740,  when  it  was*  discov- 
ered by  a  Prussian  officer  in  Silesia.  Frederick  the  Second 
ornamented  his  palace  Sans  Souci  with  this  mineral. 

The  common  people  of  Silesia  wear  the  chrysoprase 
around  the  neck  as  a  charm  against  pains. 

Chrysoprase  occurs  massive  and  in  plates ;  the  fracture 
is  even  and  splintery;  it  is  translucent;  lustre,  resinous; 
sometimes  dull  apple-green,  grass-green,  olive-green,  and 
whitish-green  color ;  it  scratches  white  glass  distinctly,  but 
is  not  so  hard  as  true  chalcedony;  specific  gravity,  2'56 ; 
it  is  infusible  before  the  blowpipe,  but  loses  its  color  when 
heated ;  it  consists  of  silex,  with  a  little  carbonate  of  lime, 
alumina,  oxide  of  iron,  and  nickel ;  its  color  is  imparted  by 


CHRYSOPRASE.  293 

the  latter  substance.  This  mineral  is  found  in  the  serpen- 
tine of  Silesia ;  also,  in  Siberia,  and  in  the  United  States 
(in  New  Hampshire). 

Chrysoprase  is  used  in  jewelry  and  for  various  ornamental 
purposes,  such  as  breastpins,  rings,  bracelets,  necklaces, 
seals,  &c. ;  and  the  larger  masses  are  used  for  snuff-boxes, 
cane-heads,  table-plates,  &c.  The  cutting  is  pretty  difficult, 
and  the  greatest  care  is  required  for  finishing  the  same 
with  facets,  as  it  is  easily  fissured ;  it  is  done  on  tin  or  lead 
plates  with*  emery,  keeping  the  first  constantly  wet  with 
water ;  it  is  polished  on  a  tin  plate  with  rotten-stone,  but 
the  lapidary  has  always  to  be  cautious  not  to  let  it  become 
hot,  as  it  easily  splirfters,  and  grows  opaque  and  gray. 
The  usual  cut  is  the  table  or  cabochon,  with  facets  on  the 
border ;  in  setting,  a  foil  of  green  satin  is  often  used  for  a 
back,  but  when  pure  and  of  good  color,  it  is  mounted  djour. 
Inferior  specimens  are  painted  on  the  back  with  a  mixture 
of  verdigris,  white  lead,  and  gum  mastic,  or  with  sap-green. 

The  chrysoprase  loses  its  color  by  wearing;  heat  and 
sunlight  likewise  cause  it  to  fade,  and  render  it  dark  and 
cloudy ;  but  the  color  may  be  restored  by  keeping  it  in  a 
wet  or  moist  place,  such  as  a  cellar,  in  wet  cotton  or  sponge, 
or  even  by  dipping  it  in  a  solution  of  nitrate  of  nickel, 
which  serves  likewise  to  improve  the  inferior  qualities. 

Very  fine  imitations  in  paste  may  be  made  by  mixing 

1000  parts  of  strass  with 

5     "     of  oxide  of  iron,  and 
8     "      of  oxide  of  nickel. 

The  chrysoprase  is  subject  to  a  great  many  faults,  such 
as  fissures,  either  natural  or  received  in  cutting ;  oily  whitish 
spots,  pale  gray  flaws  and  stripes,  and  sometimes  small 
grains  of  clay  of  reddish  color,  intermixed  in  the  interior  of 
the  stone ;  but  when  pure,  the  chrysoprase  has  always  been 


294 


A  POPULAR  TREATISE  ON  GEMS. 


a  great  favorite.  A  good  seal  or  ring  stone  may  be  worth 
from  twenty-five  to  thirty  dollars,  and  smaller  specimens 
from  one  to  five  dollars.  The  apple-green  variety  is  most 
valued,  and  a  specimen  one  line  long  by  one  half  broad, 
has  been  sold  at  from  fifty  to  one  hundred  and  fifty  dollars. 
At  Paris,  an  oval  chrysoprase,  eight  lines  long  and  seven  lines, 
broad,  was-  sold  for  three  hundred  and  ten  francs.  The 
price  generally  has  decreased  of  late,  on  account  of  the 
great  quantity  cut  from  the  mines,  which  have  recently 
been  covered  up,  in  order  to  raise  its  value  again.  At  the 
royal  palace  of  Potsdam,  in  Prussia,  are  two  tables  of  chrys- 
oprase, the  plates  of  which  are  three  feet  long,  two  feet 
broad,  and  two  inches  thick. 


CHRYSOLITE,     PERIDOT,    OLIVIN. 

The  name  of  this  stone  is  of  Greek  origin,  and  was  well 
known  to  the  ancients,  although  it  is  undecided  whether 
they  designated  the  same  mineral  by  this  name  that  we  do 
at  the  present  time,  for  they  make  it  in  their  writings  to  be 
either  the.  topaz  or  goldstone,  or  the  transparent  gold- 
yellow  stone. 

The  chrysolite  occurs  in  prismatic  forms,  generally  a 
right  prism  with  rectangular  bases;  also,  in  angular 
rounded  crystalline  grains  or  massive ; 
the  fracture  is  conchoidal ;  it  is  trans- 
parent and  translucent;  it  possesses 
powerful  double-refracting  power ;  its 
lustre  is  vitreous  and  resinous;  the 
lateral  planes  of  the  crystals  are  some- 
times striated ;  the  color  is  olive-green, 
turning  to  yellowish  and  brownish; 
it  scratches  glass  indistinctly,  and  is 
attacked  by  topaz ;  hardness,  6'5 ; 


Fig.  10. 


CHRYSOLITE.  295 

specific  gravity,  3"33  to  3'44 ;  becomes  electric  by  rubbing ; 
is  infusible  by  itself  before  the  blowpipe,  but  is  dissolved 
into  a  transparent  pale-green  bead  with  borax;  acids  do 
not  affect  it ;  it  consists  of  magnesia,  silica,  and  oxfde  of 
iron.  Chrysolite  is  found  particularly  in  basalt,  trap,  green- 
stone, porphyry,  and  lav% ;  sometimes  in  alluvial  deposits 
and  the  sands  of  rivers. 

The  perfectly  crystallized  chrysolite  is  brought  from 
Constantinople,  but  its  true  locality  is  unknown ;  less  dis- 
tinct crystallizations  occur  imbedded  in  Java  at  Vesuvius 
and  the  Isle  of  Bourbon ;  imbedded  in  obsidian  at  Reel  del 
Monte,. in  Mexico;  among  sand  at  Expaillie,  in  Auvergne, 
in  pale-green  transparent  crystals. 

Egypt,  Natolia,  and  Brazil  are  the  principal  localities 
for  the  prismatic  chrysolite;  the  oh* vin  is  more  frequently 
found  in  imbedded  crystals,  and  granular  aggregations,  in 
the  basalts  of  the  Habichtswald,  the  Eiffel,  the  Upper 
Palatinate,  Geysingburg  near  Altenburg,  Kapferistein.  in 
Styria,  and  in  the  sienite  at  Elfaden  in  Sweden.  The  brown 
variety  (hyalosiderite)  is-  found  at  Sabbach  and  Iringen  on 
the  Kaiserstahl,  and  hi  dolorite,  near  Rpburg  in  Baden. 
Crystals  of  olivin,  several  inches  in  length,  occur  in  green- 
stone, at  Unkle  near  Bonn,  on  the  Rhine,  and  it  is  a  fre- 
quent ingredient  of  meteoric  stones. 

The  word  chrysolite  is  derived  from  %pv0o$,  gold,  and 
/U0of,  stone,  in  allusion  to  its  color. 

The  dark-colored  peridots,  which  take  a  high  polish,  are 
now  much  worn  in  Europe ;  they  lose,  however,  their  gloss 
very  soon,  on  account  of  their  softening. 

The  ligurite  is  a  species  of  chrysolite  of  an  apple-green 
color,  is  transparent  and  of  uneven  fracture;  hardness,  5 '3  ; 
specific  gravity,  3*49.  Its /4|kimary  form  is  an  oblique 
rhombic  prism;  the  ligurite  contains  some  alumina  and 
lime  in  addition  to  the  composition  of  the  chrysolite  ;  it  is 


296  A  POPULAH  TREATISE  ON  GEMS. 

considered  a  superior  gem  to  chrysolite,  both  in  color  and 
transparency.  It  occurs  in  a  talcose  rock  on  the  banks  of 
the  Stura,  in  the  Apennines  of  Liguria  ;  it  does  not  become 
electrfc  by  heat  or  friction. 

The  bot.tlestone  of  Moravia  is  likewise  a  species  of  chrys 
olite,  of  dirty-green  and  grayisto-green  colors,  does  not 
occur  crystallized,  but  in  flat  pieces  of  about  an  inch  in  size ; 
some  specimens  which  the  author  collected  in  his  youth,  in 
Moravia,  were  fair  specimens  suitable  for  cutting,  their 
color  being  dark-green. 

The  chrysolite  is  cut  on  a  leaden  wheel  with  emery,  and 
is  polished  on  a  tin  plate  with  rotten-stone  or  oil  of  vitriol. 
Sometime^  pale  stones  are  finally  polished  with  some  olive 
oil,  which,  raises  the  color  considerably :  this  last  operation 
is  applied  to  restore  its  lustre,  after  the  chrysolite  becomes 
dull  'by  wearing.  The  form  is  that  ojf  a  rose  or  table  cut ; 
also  in  pavilion ;  and  when  set,  gold  foil  is  used  for  its  base : 
the -pale-colored  chrysolite  looks  well  with  a  green-colored 
copper  foil ;  dark  chrysolites  may  be  rendered  clearer  by  a 
careful  calcination.  +•'. 

The  chrysolite^  used  for  rings  and  pins,  but  does  not 
stand  in  high  estimation,  not  possessing  either  a  distin- 
guished color,  strong  lustre,  or  great  hardness,  and  losing 
its  polish  by  wearing ;  on  account  of  its  softness,  it  wears 
off  at  the  edges.  Very  good  specimens  of  peridot  from 
Brazil  were  brought  into  this  country  from  France,  and 
commanded  a  good  price,  a  few  years  ago,  viz :  from  ten 
to  fifteen  dollars  a  carat. 

Chrysolite  was  much  esteemed  by  the  ancients ;  Queen 
Berenice  received  a  chrysolite  as  a  present  from  Phile- 
mon, lieutenant  of  King  Ptolomeus. 

Cleopatra  likewise  gave  one  to  Antony.  Louis  XIII. 
brought  chrysolite  into  fashion  at  his  court. 

Among  the  engravings  in  chrysolite  is  one  of  the  Em- 


IOLITE. 


29Y 


peress  Sabine,  which  is  in  the  cabinet  of  Crispi,  at  Ferrara. 
Among  the  most  extraordinary  engravings  in  chrysolite, 
is  one  representing  Ptolomeus-Oulet,  king  of  Egypt,  and 
the  Nuptials  of  Cupid. 


IOLITE. 

This  mineral  has  for  a  long  time  been  brought  from 
Spain,  but  has  lately  been  made  known  and  brought  into 
notice  by  Cordier,  afte'r  whom  it  received  the  name  cor- 
dierite  /  it  is  called  likewise  steinheilite^  and  has  several 
other  names,  which  I  will  mention,  in  order  that  the  reader 
may  not  be  confused  when  the  same  mineral  is  presented 
as  a  gem,  under  different  names;  the  most  appropriate 
name  is  dichroite,  from  its  property  of  displaying  two 
colors  when  held  in  different  directions ;  it  is  also  known 
aspeliom  and  prismatic  quartz. 

It  occurs  in  regular  six  and  twelve  sided  prisms ;  also,  in 
crystalline  grains,  massive,  and  in  pebbles ;  its  fracture  is 
conchoidal  and  uneven ;  it  is  transparent, 
exhibiting  an  indigo-blue  color  when  held 
in  the  direction  of  its  axis,  or  viewed  by 
transmitted  light,  and  appearing  brown- 
ish-yellow when  held  at  right  angles ;  it 
possesses  some  double-refracting  power. 
Sometimes  a  ray  of  light,  resembling  that 
of  the  star-sapphire,  may  be  perceived  in 
iolite,  particularly  when  cut;  it  has  a 
vitreous  lustre ;  its  colors  are  violet-blue 
and  indigo-blue,  sometimes  with  a  tinge 


Fig.  11, 


of  black  and  bluish-gray.  It  scratches  glass,  and  is  attacked 
by  topaz ;  its  streak-powder  is  white ;  hardness,  6'5 ;  it 
ha's  a  specific  gravity  of  2*88.  By  rubbing,  it  becomes 
electric,  and  assumes  polarity  by  heating ;  it  is  difficult  to 


298          A  POPULAR  TREATISE  ON  GEMS. 

fuse  on  the  edges,  and  becomes  then  a  grayish-green 
enamel :  borax  fuses  it  into  a  diaphanous  glass ;  acids  have 
no  effect  upon  it ;  it  consists  of  magnesia,  alumina,  and 
silica,  with  some  oxide  of  iron  and  water. 

It  is  often  found  under  the  names  of  lynx  and  water 
sapphire,  the  first  of  a  pale  and  the  latter  of  a  darkish  blue 
color.  It  is  found  in  primitive  rocks ;  also,  in  blue  day, 
in  copper  pyrites,  in  quartz  or  felspar,  and  in  small  de- 
tached masses ;  the  localities  are  at  Baldenmays  in  Bavaria, 
occasionally  in  perfect  crystallizations,  but  usually  massive ; 
'  it  is  associated  with  magnetic  pyrites.  The  variety  from 
this  locality  has  been  called  peliom,  from  its  peculiar  smoky- 
blue  color,  from  rrehiog.  It  occurs  in  quartz,  at  Ujordlero- 
soak,  in  Greenland  ;  in  granite,  at  Cape  de  Gata,  in  Spain  ; 
at  Arehdal,  in  Norway ;  at  Orrijervi,  in  Finland ;  at  Tuna- 
berg,  in  Sweden,  &c.  Ceylon  affords  a  transparent  variety 
in  small  rolled  masses  of  an  intense  blue  color.  At  Had- 
dam,  Connecticut,  it  is  associated  with  garnet  and  anthoph- 
yllite  in  gneiss.  It  is  occasionally  employed  as  a  gem, 
and  when  cut  exhibits  its  dichroism,  or  different  colors  in 
different  directions.  The  name  iolite  is  derived  from  tov, 
a  violet,  and  /U0o£,  stone,  in  allusion  to  its  color.  From  its 
property  of  exhibiting  different  colors  according  to  the 
direction  in  which  it  was  viewed,  it  has  also  been  named 
dichroite,  from  61$,  double,  and  %poa,  color. 

The  hydrous*  iolite,  from  Sweden,  of  grayish-brown  or 
dark  olive-green .  color,  is  a  very  soft  mineral ;  hardness, 
3'75  ;  occurs  in  red  granite,  accompanied  by  a  light  bluish- 
gray  iolite. 

If  the  stone  is  perfectly  pure,  it  is  used  for  rings  and 
breastpins;  is  cut  on  a  copper  wheel  with  emery,  and 
polished  on  a  tin  plate  with  rotten-stone,  and  receives  the 
form  of  a  cabochon,  in  order  to  let  it  display  its  proper 
colors,  and  in  a  cube  form.  Its  price  is  not  very  high  ;  the 


PRECIOUS    OPAL.  299 

jewellers  value  it  as  an  inferior  quality  of  the  sapphire, 
without  paying  any  regard  to  its  phenomena  of  light. 
Good-sized  specimens  are  sold  at  about  eight  to  ten  dollars 
each  ;  at  Paris,  a  good  iolite,  ten  lines  long  and  eight  and 
a  half  broad,  was  sold  for  one  hundred  and  sixty  francs. 
When,  a  couple  of  years  ago,  the  iolite  was  discovered  by 
Professor  Mather,  at  Haddam,  Connecticut,  it  promised  to 
be  a  valuable  acquisition  to  American  gems ;  but  the 
suppfy  was  very  scant,  and  its  original  locality  appears  to 
be  exhausted.  Professor  Torrey  possesses  a  fine  seal,  in 
the  form  of  a  cube,  from  that  locality,  which  displays  its 
properties  to  the  greatest  perfection. 

A  blue  quartz  is  occasionally  sold  for  iolite,  but  it  may 
easily  be  distinguished  by  its  colors  and  hardness.  Sapphire 
is  considerably  harder  than  the  iolite. 

OPAL. 

The  precious  variety  of  this  mineral  was  known  to  the 
ancients,  and  received  its  name  on  account  of  the  "play  of 
colors  which  it  has.  The  opal  has  a  great  many  varieties, 
which  are  all  considered  more  or  less  gems,  and  find  their 
application  in  jewelry ;  they  will  therefore  be  treated 
separately.  But,  as  general  characters,  it  may  now  be  men- 
tioned that  opal  scratches  glass  but  slightly,  while  it  is 
marked  by  rock-crystal ;  it  has  a  specific  gravity  of  2'OG.to 
2'11  ;  it  is  infusible  before  the  blowpipe,  but  decrepitates 
and  falls  into  splinters ;  it  also  dissolves  with  borax.  Opal 
consists  of  silica  with  water,  some  oxide  of  iron,  and  some- 
times alumina. 

•  •        '  :         *      • 

PRECIOUS    OPAL. 

This  gem  derives  its  name  from  the  Greek  word  sig 
nifying  the  eye,  for  the  ancients  believed  that  this  stone 


300  A    POPULAR    TllEATISE    ON    GEMS. 

had  the. power  of  strengthening  the  eye.  It  was  highly 
esteemed  by  them,  as  we  learn  from  l^liny,  who  thought 
that  the  play  of  color  originates  from  the  beautiful  colors 
of  the  carbuncle,  amethyst,  and  emerald. 

The  phenomenon  of  the  play  of  colors  in  the  precious 
opal  has  not  yet  been  satisfactorily  explained.  Hatiy  attrib- 
utes it  to  the  fissures  of  the  interior  being  filled  with  films 
of  air,  agreeably  with  the  law  of  Newton's  colored  rings, 
when  two  pieces  of  glass  are  pressed  together.  Mohs'con- 
tradicts  this  theory  upon  reasonable  grounds,  which  are,  that 
the  phenomenon  would  present  merely  a  kind;  of  irides- 
cence. Brewster  concludes  that  it  is  owing  to  fissures  and 
cracks  in  the  interior  of  the  mass,  not  accidental  but  of 
a  uniform  shape,  and  which  reflect  the  tints  of  Kewton's 
scale ;  but  it  is,  in  my  opinion,  sufficiently  plausible,  that 
the  unequal  division  of  smaller  and  larger  cavities,  which 
are  filled  with  water,  produces  the  prismatic  colors,  and  for 
the  simple  reason  that"  the  opal  which  grows,  after  a  while, 
dull  and  opaque,  may  be  restored  to  its  former  beauty  if 
put  for  ti  short  time  in  water  or  oil. 

Although  the  precious  opal  was  never  found  in  the  East, 
yet  it  bears  the  name  of  Oriental  opal  among  jewellers: 
for  in  former  times  opals  were  carried  by  the  Grecian  and 
Turkish  merchants  from  Hungary,  their  native  locality, 
to  the  Indies,  and  brought  back  by  the  way  of  Holland 
to  Europe,  as  Oriental  opals.  The  precious  opal  is  found, 
in  small  irregular  gangues,  nests  of  the  trachytic  por- 
phyry formation  and  its  conglomerates,  in  Hungary,  par- 
ticularly in  the  neighborhood  of  the  village  of  Czerwin- 
ccza ;  also,  in  the  Faroe  Islands,  Saxony,  and  South  America. 
The  Hungarian  opal  is  found  of  various  qualities,  and  «is 
obtained  from  mines  which  have  been  wrought  for  several 
centuries ;  and,  according  -to  the  archives  of  that  part  of 
the  country,  there  were,  in  the  year  1400,  more  than  three 


PRECIOUS    OPAL.  301 

hundred  workmen  engaged  at  the  mines  near  tlt£  above 
village ;  whereas  there  are  but  thirty  at  present  engaged 
there,  on  account  of  the  scarcity  of  large  suitable  speci 
mens. 

The  precious  opal  is  principally  used  for  rings,  ear-rings, 
necklaces,  and  diadems ;  the  smaller  specimens  for  mount- 
ing snuff-boxes,  rings,  chains,  &c.  It  is  ground  on  a  leaden 
wheel  with  emery,  and  is  polished  with  rotten-stone  and 
water  on  a  wooden  wheel ;  and,  in  order  to  increase  its 
lustre,  it  is  lastly  rubbed  with  putty,  by  means  of  buckskin, 
or  a  woollen  rag  and  red  chalk.  Its  form  is  generally  that 
of  a  semicircle,  lens,  or  oval;  sometimes  of  a  table,  and 
then  also  with  some  facets ;  but  great  care  has  to  be  taken 
that  the  edges,  on  account  of  the  softness  of  the  stone,  do 
not  wear  off.  It  is  also  apt  to  spring  in  a  temperature  sud- 
denly changing.  When  mounted,  it  receives  a  colored 
foil,  or  a  variegated  silk  stuff,  or  a  peacock-feather  on  the 
back,  but  it  looks  best  in  a  black  casing. 

Cracks  and  fissures  may  be  removed  by  leaving  the  pre- 
cious opal  for  some  time  in  oil.  Very  frequently  the  pre- 
cious opal  is  distributed  in  small  particles  in  the  matrix, 
called  mother  of  opal,  which  is  cut  by  the  jewellers  as 
boxes,  and  other  ornaments  4  and  very  often,  too,  this 
matrix  is  plunged  into  oil,  and  exposed  to  a  moderate  heat, 
whereby  the  base  grows  b.lacker,  and  the  true  precious 
opal  retains  its  ray  of  colors.  In  order  to  preserve  the 
surface  of  the  precious  opal  against  wear  and  tear,  it  is 
covered  with  a  thin  plate  of  quartz  crystal.  The  precious 
opal  still  stands  in  very  high  estimation,  and  is  considered 
one  of  the  most  valuable  gems.  The  size  and  the  beauty 
displayed  by  its  colors  determine  its  value ;  those  playing 
in  the  red  and  green  colors  bear  the  highest  price.  Its 
value  has  latterly  increased  on  account  of  the  scarcity  of 
the  larger  specimens.  Formerly,  a  solitary  large  precious 


302  A  POPULAR  TREATISE  ON  GEMS. 

opal,  playing  in  the  red  color,  was  sold  for  two  to  three 
hundred  ducats;  and  one  playing  in  both  red  and  green 
colors,  about  five  lines  long,  was  sold  at  Paris  for  two 
thousand  four  hundred  francs;  and  lately  a  single  opal,  of 
fine  colors,  and  the  size  of  a  dollar,  was  sold  near  the 
locality  for  three  hundred  thousand  florins ;  in  this  country 
precious  opals  are  sold  by  the  importers  at  the  rate  of 
four  to  ten  dollars  per  carat,  and  single  specimens,  suitable 
for  pins  or  rings,  from  two  to  twenty  dollars.  The  mother 
of  opal  is,  however,  much  cheaper ;  one  of  five  lines  size  is 
sold  for  three  to  five  dollars. 

All  experiments  for  imitating  the  precious  opal  have 
hitherto  proved  fruitless ;  they  were  made  either  by  pre- 
paring an  enamel  and  adding  several  metallic  oxides,  or  by 
affixing  to  the  back  of  a  clear  or  common  opal  or  enamel,  a 
polished  thin  plate  of  the  mother  of  pearl,  which  may  some- 
times deceive  the  ignorant. 

The  precious  opal,  when  large  and  exhibiting  its  peculiar 
play  of  colors  in  perfection,  is  a  gem  of  considerable  value; 
it  was  used  as  an  ornament  among  the  Greeks  and  Romans, 
and  was  called  opalus  ;  also  paederos  (Ttaidepd)?) ,  in  allusion 
to  its  color  and  lustre  as  expressed  in  the  Orphic  poem : 
"  Ipeprov  repeva  xpoa  naidbs, — having  the  delicate  com- 
plexion of  a  lovely  youth."  The  most  magnificent  Hunga- 
rian opal  in  the  London  Exhibition,  called  "the  mountain 
of  light" — a  very  appropriate  name — weighed  526 £  carats, 
and  was  estimated  at  4000  pounds  sterling. 

From  Honduras,  at  Gracias  a  Dios,  large  quantities  of 
opals  have  been  imported  into  this  city  for  the  last  ten  years, 
at  first  by  the  late  Mr.  De  la  Raye,  and  latterly  by  Mr. 
Aaron  C.  Burr ;  and  many  large  and  beautifully  cut  speci- 
mens are  in  the  possession  of  Mr.  B.  Palmer,  of  this  city; 
they  are  by  no  means  inferior  to  the  Hungarian  opal.  A 
very  large  opal,  cut  and  polished  by  himself,  which  he 


PRECIOUS   OPAL.  303 

values  at  four  thousand  dollars,  is  one  and  three  quarters 
inches  long  by  one  and  a  quarter  inches  wide ;  another, 
one  and  a  quarter  inches  long  by  one  inch  wide,  he  prizes 
at.  seven  hundred  and  fifty  dollars;  and  a  third,  one  and 
one  eighth  inches  long  by  one  inch  wide,  he  values  at  four 
hundred  and  fifty  dollars. 

The  ancients  held  the  opal  in  great  estimation,  and  the 
anecdote  of  the  Roman  senator,  Nonius,  is  well  known — 
that  he  preferred  exile  to  parting  with  a  magnificent  opal 
which  Marc  Antony  coveted. 

In  the  French  crown-jewels  are  two  very  large  and 
beautiful  opals.  One  is  set  in  the  centre  of  the  Order  of 
the  Golden  Fleece,  and  the  other  forms  the  clasp  of  the 
imperial  cloak.  They  were  purchased  for  75,000  francs. 
The  Empress  Josephine  possessed  the  unique  oppl  which 
was  called  "  The  Great  Fire  of  Troy,"  on  account  of  the 
great  fire  sparkles. 

The  Vienna  Cabinet  possesses  a  very  large  opal,  but 
unfortunately  it  is  cracked.  Count  Walewski,  who  is  a 
great  amateur  of  gems,  possesses  a  very  beautiful  opal, 
which  is  oval,  the  size  of  a  franc-piece,  and  is  said  to  be 
extraordinarily  brilliant, 

The  Imperial  Mineralogical  Cabinet  at  Vienna,  contains 
the  most  celebrated  specimens  of  precious  opal ;  one,  par- 
ticularly, may  be  mentioned  here:  it  is  four  and  three 
quarter  inches  long,  two  and  a  half  inches  thick,  and  weighs 
seventeen  ounces.  It  was  discovered  about'  1770,  at  the 
above  locality,  and  transported  to  Vienna.  It  displays  the 
most  magnificent  colors ;  is  perfectly  pure,  and  not  accom- 
panied by  any.  matrix.  Half  a  million  of  florins  were 
offered  for  it  by  a  jeweller  of  Amsterdam,  and  refused  on 
account  of  its  uniqueness ;  and  the  Viennese  have  not  yet 
dared  to  put  even  any  approximate  value  upon  it. 


304  A  POPULAR  TREATISE  ON  GEMS. 


FIRE  OPAL. 

This  mineral  was  first  brought  into  notice  by  Baron 
Humboldt,  who  found  it  in  Mexico. 

It  occurs  massive ;  has  a  conchoidal  fracture ;  is  trans- 
parent ;  of  strong  vitreous  lustre  ;  color,  hyacinth-red,  run- 
ning into  honey,  wine-yellow,  showing  carmine-red  and 
greenish  reflections ;  sometimes  containing  dendritic  draw- 
ings. Its  specific  gravity  is  2 '02  ;  loses  one  and  a  half  per 
cent,  by  calcination,  and  leaves  pale  flesh-red  fragments.  It 
is  found  in  the  trachytic  porphyry,  in  Mexico,  and  in  the 
amygdaloid  of  the  Faroe  Islands. 

As  the  fire  opal  is  very  little  known,  it  has  not  yet 
been  employed  in  jewelry,  but  bids  fair  to  find  applica- 
tions. It  is  ground  on  a  leaden  wheel  with  emery,  and 
polished  with  rotten-stone  on  a  wooden  wheel.  The  forms 
of  cabochon,  table,  or  pavilion,  might  suit  very  well  as  ring- 
stones. 

The  cabinet  of  the  university  of  Bonn  possesses  a  very 
large  and  fine  fire  opal,  of  the  size  of  the  fist.  The  largest 
specimen  I  have  seen  is  in  the  royal  mineral ogical  cabinet 
at  Berlin,  which  was  deposited  by  Baron  Humboldt  on 
his  return  from  South  America,  and  which,  if  I  recollect  it 
well  enough  from  the  year  1827,  must  be  at  least  six  inches 
long  and  four  inches  thick.  This  is  the  largest  specimen 
he  ever  found.  A  collection  of  six  shades  of  fire  opal,  with 
six  more  varieties  of  the  other  opals,  was  presented  to  me 
in  the  year  1828,  when  in  Berlin,  by  the  Counsellor  Berge- 
man,  who  received  at  that  time  a  considerable  quantity  of 
polished  specimens  from  the  Faroe  Islands,  but  all  of  small 
size.  A  splendid  collection  of  fire  opals  was  brought  from 
Guatemala  some  years  ago  to  this  country.  It  is  also  called 
girasol,  from  its  bright  hyacinth-red  tints. 


HYDROPHANE.  V     ,          305 


CO3CMOX    OPAL. 

This  mineral  occurs  massive  and  in  rolled  pieo^;  also  as 
stalactites;  has  a  cOnchoidal  fracture;  is  transient  and 
semi-transparent ;  has  a  strong  vitreous  and  resinous  lustre ; 
its  colors  are.  milky,  yellow,  reddish,  greenish- white,  honey- 
yellow,  wine-yellow,  flesh,  brick-red,  and  olive-green  ;  some- 
times dendritic  (moss  opal).  Its  specific  gravity  is  1 '9  to  2*1. 

The  wax  or  pitch  opal  is  subordinate  to  this  variety. 
It  is  found  in  the  same  rocks  as  the  precious  opal,  in  Hun- 
gary ;  in  the  hematite  rocks  of  Saxony ;  in  the  serpentine 
of  Silesia;  in  cavities  of  trap  and  the  amygdaloid  rocks  of 
Iceland  ;  'Faroe  Islands ;  and  in  the  United  States  (Penn- 
sylvania and  Connecticut). 

It  is  used  for  rings,  pins,  and  cane-heads ;  but  is,  on  the 
whole,  not  a  favorite  among  jewellers,  <ind  has  no  great 
value,  because  it  is  soft  and  brittle ;  fche  paste,  which  may 
be  made  from  white  enamel,  is  sometimes  much  prettier 
than  the  real  stone. 

HYDKOPHAXE. 

The  name  of  this  variety  of  opal  has  reference  to  its 
peculiar  property  of  becoming  transparent  and  opalescent 
after  immersion  in  water.  The  ancients  called  this  stone 
lapis  mutabilis,  and  achates  oculus  mundi.  It  is  A  commpn 
or  precious  opal,  of  pordns  texture;  adheres  strongly  to  the 
tongue ;  is  translucent,  and  absorb*  water  with  avidity, 
giving  off  at  the  same  time  air-bubbles;  it  thus  assumes  a 
high  degree  of  transparency,  and  sometimes  the  property 
of  displaying  the  finest  prismatic  colors,  equal  to  the  pre- 
cious opal.  This  phenomenon  tends  strongly  to  explain  the 
display  of  the  prismatic  colors  of  the  precious  opal ;  the 
more  so,  as  the  hydrophane  loSes  this  property  on  getting 
dry. 


306  A  POPULAR  TREATISE  ON  GEMS. 

It  has,  when  dry,  a  white,  yellowish,  or  reddish  color,  and 
a  specific  gravity  of  1*95  to  2'01 ;  and  according  to  Hatly, 
a  hydroplane,  having  been  immersed  for  four  minutes  in 
water,  gaiRd  thirty-four  centigrammes: 

The  hydrophane  is  found  in  the  porphyry  of  Hungary, 
France,  Iceland,  and  the  Faroe  Islands.  Large  pieces  of 
good  and  fine  specimens  of  hydrophane  are  wrought  and 
used  in  the  same  manner  as  the  precious  opal. 

It  is  said  that  the  hydrophane  becomes  much  quicker 
transparent  in  warm  than  in  cold  water ;  the  quickest  in 
spirits  of  wine ;  after  which,  it  loses  this  property  the 
sooner ;  but  when  boiled  in  oil,  it  retains  it,  to  a  certain 
extent,  for  years. 

If  the  hydrophane  is  well  dried  and  soaked  in  melted 
white  wax,  or  spermaceti,  it  assumes  the  property,  when 
warmed,  of  becoming  translucent,  and  of  displaying  brown- 
ish-yellow or  gray  colors ;  it  is  then  called  pyrophane. 

The  hydrophane  was  formerly  colored  violet  or  red,  by 
means  of  a  decoction- of  logwood  and  alum. 

The  price  of  hydrophane  is  very  high,  on  account. of  its 
great  scarcity,  and  because  it  is  very  seldom  found  in  large 
lumps. 

"SEMI-OPAL. 

This  variety  of  opal  was  formerly  considered  to  be  a 
pitch-stone,  and  if  it  assumes  the  fonn  of  petrified  wood,  it 
is  called  wood  opal.  It  has  a  conchoidal  and  even  fracture ; 
it  is  translucent  and  opaque;  of  a  resinous  and  vitreous 
lustre ;  its  colors  are  yellowish,  grayish,  and  brownish,  the 
colors  running  mostly «dnto  one  another ;  sometimes  the 
colors  divide  themselves  ribbon-like.  The  wood  opal  is 
mdstly  brownish,  and  displays,  more  or  less,  a  ligneous 
aspect,  with  the  form  of  branches. 

The  semi-opal  is  found  in  gangues,  in  the  trachytic 


CACHELONG.  307 

porphyry  in  Hungary,  in  the  serpentine  in  Silesia,  in  the* 
amygdaloid  in  Iceland  and  the  Faroe  Islands ;  likewise  in 
Moravia,  Saxony,  France,  Greenland,  and  in  the  United 
States  (Maryland  and  Pennsylvania). 

The  semi-opal,  on  account  of  its  taking  a  high  polish,  is 
used  for  many  purposes  in  jewelry.  There  is  an  estab- 
lishment for  manufacturing  snuff-boxes  from  wood  opal,  in 
Vienna,  and  lately  the  varieties  of  wood  opal,  with  layers  of 
chalcedony,  or  semi-opal,  have  found  a  useful  application  for 
the  cutting  of  cameos.  The  semi-opal  is  ground  and  polished 
like  the  precious  opal,  but  with  more  difficulty,  on  account 
of  its  being  more  brittle.  The  form  which  it  easily  receives 
is  in  cabochon,  but  without  facets.  The  price  of  the  semi 
or  wood  opal  is  low. 

CACHELONG. 

According  to  Blumenbach,  the  name  of  this  mineral  is  pf 
Mongolian  derivation,  meaning  "  a  pretty  stone ;"  and  ac- 
cording to  Phillipps  it  receives  its  name  from  the  river  Cach, 
in  Bucharia,  on  whose  shores  it  occurs  frequently  in  loose 
conglomerates.  This  mineral  has  been  arranged  under  the 
head  of  chalcedony,  but  properly  belongs  to  opal. 

It  occurs  massive,  as  a  covering  of  other  minerals,  rarely 
reniform,  often  traversed  with  fissures  in  different  directions. 
It  has  a  conchoidal  fracture ;  is  opaque,  and  of  a  pearly 
lustre ;  milky- white,  turning  sometimes  to  a  yellow  or  red 
color,  and  exhibits  dendritic  figures  of  manganese  or  green 
earth.  ;  It  scratches  white  glass ;  has  a  specific  gravity  of 
2'2 ;  it  decrepitates  when  first  brought  before  the  blow- 
pipe, but  yet  undergoes  no  change ;  clissolves  with  borax, 
slowly,  at  a  white  heat. 

It  is  found  in  the  same  manner  as  chalcedony,  some- 
times incrusting  or  penetrating  it,  in  the  amygdaloid  of 
Iceland,  Greenland,  the  Faroe  Islands,  the  hematite  of 


308          A  POPULAR  TREATISE  OX  GEMS. 

Carinthia,  the  United  States  (Massachusetts),  and  Neva 
Scotia ;  in  Bucharia,  in  the  sand  of  the  river  Cach,  it  is 
found  loose.  • 

Caclielong  being  generally  constituted  of  layers  of  differ- 
ent degrees  of  hardness,  the  sculptors  of  cameos  profit 
thereby,  for  the  purpose  of  producing  better  bas-reliefs. 

In  the  Imperial  Library,  at  Paris,  is  a  very  fine  cameo, 
representing  Valentine  III. 

Cachelong  is  much  used  in  jewelry,  for  rings,  seals,  &c. 
The  Calmucks  of  Bucharia  manufacture  of  it  tools  and 
other  domestic  articles.  •  It  is  cut  on  a  copper  wheel  with 
emery,  in  cabochon,  and  receives  the  polish  on  lead  plates 
by  means  of  rotten-stone  and  putty.  The  price  of  the 
cachelong  is  pretty  considerable,  on  account  of  its  beauty 
and  scarcity,  as  the  specimens  most  frequently  found  in 
the  above  localities  are  seldom  in  layers  of  more  than  one 
quarter  of  a  line,  alternating  with  chalcedony. 

JASPER    OPAL. 

This  mineral  stands  between  jasper  and  opal;  and,  al- 
though considered  by  Werner  as  belonging  to  the  first, 
ought,  nevertheless,  more  properly  to  be  arranged  with  the 
opal,  on  account  of  its  containing  water  in  its. composition. 

The  jasper  opal  occurs  massive,  in  specks,  stalactiform,  and 
in  geodic  masses;  it  has  a  conch oidal  fracture;  is  translu- 
cent on  the  edges,  or  opaque ;  is  of  a  strong  resinous  lustre; 
its  colors  are  gray,  yellow,  red,  and  brown.  Its  specific 
gravity  is  2'0  to  2*1.  „  It  consists  of  silica,  water,  and  oxide 
of  iron,  amounting  to  forty-seven  per  cent.  It  is  found  in 
the  trachytic  breccias  of  Hungary;  also,  in  Saxony  -and 
Siberia.  The  best  light  and  pure  specimens  are  used  for 
dagger  and  sword  handles  in  Turkey.  The  price  of  jasper 
opal  is  low. 


OBSIDIAN.  309 


OBSIDIAN. 

This  mineral  was  familiarly  known  to  the  ancients,  and 
its  name  is  said  to  be  derived  from  a  Rpman,  who  first 
brought  it  to  Rome  from  Ethiopia.  Pliny  states  that  the 
Romans  manufactured  mirrors  and  gems  from  it;  the 
Mexicans  and  Peruvians  manufactured  their  knives,  razors, 
and  sword-blades  from  obsidian,  which  appears  to  have 
served  as  a  complete  substitute  for  other  materials  with 
those  nations,  who  were  yet  unacquainted  with  the  use  of 
iron  for  weapons  and  utensils  of  various  kinds.  Baron 
Humboldt  says  that  Cortez  mentioned,  in  his  letter  to  the 
Emperor  Charles  V.,  having  seen  razors  of  obsidian  at 
Tenochittan ;  and  the  above  naturalist  likewise  discovered, 
on  the  Sierra  de  las  Nabajaz,  in  New  Spain,  the  old  shaft 
that  was  used  for  raising  the  rough  obsidian,  with  relics 
of  the  tools  and  half-finished  utensils. 

The  inhabitants  of  Quito  manufactured  magnificent  mir- 
rors from  obsidian,  and  those. of  the  Azores  and  Ascension 
islands,  and  Guiana,  used  splinters  of  obsidian  as  points  for 
their  lances,  razors,  &c. 

Specimens  of  arrows  and  other  articles,  such  as  octangu- 
lar wedges,  were  presented  a  few  years  ago  to  the  New 
York  Lyceum  of  Natural  History,  being  relics  from  the 
ruins  of  Palenque.  In  the  collection  of  Columbia  College 
are  some  razors,  or  sacrificial  knives,  the  gift  of  the  Hon. 
J.  R.  Poinsett. 

Obsidian  occurs  massive,  in  roundish  or  obtuse  lumps, 
balls,  and  grains ;  has  a  conchoidal  fracture ;  is  semi-trans- 
parent and  translucent  on  the  edges ;  it  has  a  strong  vitre- 
ous, and  sometimes  even  metallic  lustre;  its  colors  are 
either  pure  black,  grayish,  brownish,  greenish-black,  yellow, 
blue,  or  white,  but  seldom  red;  it  sometimes  displays  a 
peculiar  greenish-yellow  shine,  when  it  is  called  the  irides- 


310          A  POPULAR  TKEATISE  ON  GEMS. 

cent  obsidian ;  there  is  rarely  more  than  one  color  in  the 
same  specimen  with  stripes  and  specks.  Obsidian  scratches 
white  glass  indifferently,  but  is  scratched  by  topaz;  its. 
streak-powder  is  white ;  it  has  'a  specific  gravity  of  2*34  to 
2'39.  Obsidian  is  sometimes  magnetic,  so  that  small  pieces 
show  their  magnetic  poles.  Before  the  blowpipe,  the  black 
variety  is  fusible  with  much  difficulty ;  and  even  at  a  white 
heat  it  does  not  melt  into  a  solid  glass ;  but  the  gray  and 
brown  variety  (marekanite)  swells  readily  into  a  spongy 
mass. 

Obsidian  consists  of  silex,  alumina,  with  a  little  potassa, 
soda,  and  oxide  of  iron. 

The  names,  Iceland  agate,  lava,  black-glass  lava,  volcanic 
lava,  are  all  synonymous,  and  the  mineral  called  bottle- 
stone,  in  round  grains  of  the  size  of  a  pea,  is  nothing  but 
a  green  obsidian. 

Obsidian,  sometimes,  forms  the  cement  of  .whole  moun- 
tain chains,  often  forms  deposits  in  the  trachyte  and  the 
streams  at  the  foot  of  some  volcano ;  also,  among  the  vol- 
canic ejections,  and  occurs  in  loose  lumps  in  the  sand  of 
rivers,  and  at  the  foot  of  mountains.  It  is  found  in  Iceland, 
Teneriffe,  the  Lipari  Islands,  Peru,  Mexico,  Sicily,  Hungary, 
Asiatic  Russia,  the  Ascension  Islands,  and  on  all  the  vol- 
canoes of  former  and  present  times. 

In  the  New  York  Lyceum  of  Natural  History  are  several 
interesting  specimens,  presented  by  Don  Correa,  of  Ta- 
basco, from  the  ruins  of  the  city  of  Palenque ;  such  as  con- 
cave or  triangular  wedges,  and  other  masses  of  obsidian, 
from  various  localities. 

It  is  employed  for  several  useful  and  ornamental  pur- 
poses ;  such  as  the  making  of  ear-rings,  necklaces,  brooches, 
snuiF-boxes,  knife  handles,  &c.  -It  is  particularly  worn  as 
mourning  jewelry;  it  requires,  however,  much  care  in 
working,  being  extremely  brittle.  It  is  ground  on  lead 


AXINTTE.  311 

wheels  with  emery,  and  polished -with  rotten-stone.  It  is 
kept  in  favor  by  the  jewellers,  on  account  of  its  high  polish ; 
but  its  value  is  very  indifferent,  excepting  that  of  the  iri- 
descent obsMian,  which  commands  a  high  price,  and  is 
sometimes  seen  cut  in  cabochon,  and  set  in  rings. 

There  is  no  doubt  but  that  obsidian  is  of  volcanic  origin^ 
being  mostly  found  in  the  neighborhood  of  volcanoes,  and 
that  it  is  a  glass,  produced  by  volcanic  fire,  as  it  is  a 
combination  of  silex  and  alkaline  substances.  The  Nep- 
tunian theorists  have  endeavored  to  prove  that  it  is  occasion- 
ally found  with  the  remains  of  decomposed  granite,  gneiss, 
and  porphyry,  with  which  it  even  alternates  in  layers. 

AXINTTE. 

The  name  of  this  mineral  is  derived  from  a  Greek  word, 
signifying  an  axe,  and  was  applied  to  it  oh  account  of  the 
resemblance  of  its  crystals  to  that  implement ;  it  is  also 
called  by  some  English  mineralogists,  thumer-stone,  from 
its  first  locality.  -;  : 

Axinite  occurs  in  a  variety  of  crystalline  forms,  which 
are  reducible  to  the  rhombic,  viz :  an  oblique  rhomb,  or 
four-sided  prism,  so  compressed  that  the  edges  appear 
sharp,  like  the  edge  of  an  axe ;  likewise}  massive  and  in 
specks ;  its  fracture  is  uneven ;  it  is  translucent  on  the 
edges,  or  sometimes  transparent;  hag  simple  refraction 
of  light ;  its  lustre  is  vitreous,  also,  resinous ;  its  colors  arc 
violet-blue,  brown,  gray,  and  yellow;  it  scratches  white 
glass,  but  is  scratched  by  topaz ;  has  a  white  streak-powder ; 
its  specific  gravity  is  3*27 ;  it  becomes  electric  by  rubbing 
or  heating;  before  the  blowpipe  it  fuses  into  a  grayish- 
brown  glass ;  acids  have  no  effect  upon  it ;  it  consists  of 
lime,  alumina,  and  silex,  with  oxide  of  iron  and  manganese. 
It  occurs  in  gangues  and  layers  of  various  formations, 


31T2  A   POPULAR   TREATISE    ON   GEMS. 

principally  the  primitive ;  and  is  found  in  Dauphine,  the 
Pyrenees,  Gothard,  Saxony  (Thum),  Norway,  &c. 

This  mineral  takes  a  very  high  polish,  particularly  those 
specimens  from  Dauphine^  but  has  hitherto,  on  account  of 
its  scarcity,  not  found  much  application  in  jewelry,  but  will 
Hereafter  be  a  great  acquisition,  as  it  may  be  used  for  rings, 
pins,  and  other  small  ornaments 

FELSPAR. 

The  varieties  of  this  mineral  are  mostly  crystallized,  and 
in  very  numerous  forms ;  but  they  are  all  distinguished  by 
two  great  characters,  which  are,  the  foliated  structure  and 
peculiar  lustre;  the  principal  form  is  an  oblique  prism 
with  unequal  sides.  Felspar  scratches  glass  and  is  scratch- 
ed by  rock  crystal ;  its  streak-powder  is  white ;  it  has  a 
specific  gravity  of  2*5  to  2*6;  before  the  blowpipe  it  fuses 
with  difficulty ;  on  charcoal  it  becomes  vitreous  and  white ; 
fuses  with  difficulty  on  the  edges  to  a  translucent  white 
enamel ;  acids  have  no  effect  upon  it ;  it  consists  of  potash, 
alumina,  and  silex. 

ADULARIA. 

This  mineral  occurs  in  crystals  (oblique  prisms  and  rhom- 
boidal  faces),  crystalline  fragments,  and  solid  masses;  its 
fracture  is  uneven;  it  is  translucent  on  the  edges;  has 
double  refraction  of  light ;  the  lustre  is  vitreous  and  pearly, 
more  especially  when  cut  and  polished ;  it  throws  out  green- 
ish and  bluish-white  chatoyant  reflections  from  the  interior ; 
it  cleaves  in  two  directions ;  the  crystals  often  present  the 
hemitrope  form,  which  in  polished  specimens  becomes  ob- 
vious from  the  different  directions  of  the  laminae;  its' colors 
are  limpid-white,  greenish,  grayish,  and  bluish,  frequently 


ADULARIA.  313 

with  a  peculiar  pearly  shine,  and  sometimes  it  is  iridescent. 
Specific  gravity,  2 '5  ;  and  softer  than  quartz. 

In  commerce,  adularia  goes  under  various  names,  such 
as  ^noon-stone,  sun-stone,  girasol,  fish-eye,  and  Ceylon  or 
water  opal.  In  the  moon-stone  the  color  is  white,  with 
small  bluish  or  greenish  shades,  but  the  base  is  semi-trans- 
parent and  milky ;  whereas  the  sun-stone  shows  a  yellow 
and  reddish  play  of  colors.  Adularia  is  found  in  gangues 
and"  cavities  of  granite,  gneiss,  and  limestone,  and  in 
pebbles  from  Ceylon,  Greenland,  Bavaria,  St.  Gothard, 
Tyrol,  Dauphine,  and  in  the  United  States, — particularly 
at  Ticonderoga,  near  Lake  Champlain,  New  York,  Mary- 
land, Pennsylvania,  Connecticut,  and  Massachusetts.  The 
adularia  from  St.  Gothard  is  found  in  very  large  masses :  I 
saw,  in  1827,  in  the  cabinet  at  Zurich,  in  Switzerland, 
groups  of  crystallized  adularia,  measuring  two  feet  in 
length  and  one  foot  in  thickness,  the  splendor  of  which 
dazzled  my  eyes. 

Adularia,  displaying  a  good  color,  and  strong  pearly 
reflections,  is  now  much  used  in  jewelry,  for  rings,  pins, 
and  other  smaller  ornaments.  Generally  specimens  which 
possess  these  qualities  are  cut  out  of  large  lumps,  then 
ground  on  a  lead  wheel,  in  cabochon  form,  and  polished 
with  rotten-stone  ;  they  are,  hi  general,  mounted  in  a  black 
case,  whence  it  best  shows  its  reflections.  The  moon-stone 
commands  a  good  price  ;  exquisitely  fine  specimens,  of  the 
size  of  a  bean,  are  worth  from  five  to  ten  dollars,  and  some 
of  them  were  sold  at  Paris,  of  six  lines  diameter,  for  seven 
hundred  and  five  francs,  and  four  lines  for  two  hundred  and 
three  francs. 

The  largest  moon-stone,  in  a  brooch,  three  fourths  of  an 
inch  in  length,  I  have  seen,  is  in  the  possession  of  Francis 
Alger,  Esq.,  of  Boston ;  and  rough  specimens,  with  most 
splendid  reflections,  I  have  admired  in  the  collection  of  the 

14 


314  A  POPULAR  TEEATISE  ON  GEMS. 

late  Dr.  M.  Gay,  of  the  same  city.  Both  these  gentlemen 
are  fortunate  in  possessing  uniques  in  this  country,  which 
are  of  no  ordinary  scientific  and  commercial  value. 

Among  the  varieties  of  felspar  may  be  named  ice-sf>ar, 
which  is  found  in  volcanic  rocks,  occurs  crystallized  in  the 
Vesuvian  lavas,  and  is  of  a  white  color. 

Murchisonite  is  a  yellowish-gray  variety  of  felspar,  from 
Dawlish  and  Arran. 

Leclite^  or  the  hettefliata  of  the  Swedes,  has  a  peculiar 
waxy  lustre  and  a  deep  flesh-red  color,  and  is  found  at 
Gryphyttan,  in  Sweden, 

Conazeranite  is  a  grayish-black  or  blackish-blue  variety, 
from  the  steep  defiles  of  Salleix,  in  the  Pyrenees ;  it  occurs 
imbedded  in  limestone. 

Variolite  is  a  dark-green  variety  of  felspar,  containing 
lighter  globular  particles ;  originally  found  in  Drac  river, 
in  France,  but  of  late  also  in  Piedmont,  Switzerland,  and 
Scotland ;  in  the  Alps  large  blocks  of  several  thousand 
pounds  are  found.  This  stone,  when  polished,  takes  a  high 
gloss,  equal  to  the  most  precious  gems.  Its  name  is  derived 
from  the  peculiar  spots  flashing  around  the  stone. 

The  name  adularia  is  derived  from  Adula,  the  ancient 
name  of  St.  Gothard,  where  the  prettiest  specimens  were 
first  discovered. 

A  very  curious  variety  has  been  found  in  Siberia,  of  a 
yellowish  color,  but  with  innumerable  gold  spots  dis- 
seminated throughout' the  whole  surface  of  the  mineral; 
these  reflections  of  light  appear  to  be  owing  to  very  small 
fissures  or  cracks,  or  to  a  confusion  of  its  lamellar  system. 
The  prettiest  specimens,  which  are  invariably  cut  in  cabo- 
chon,  look  much  like  a  reflection  of  a  star,  diverging  from 
the  centre ;  they  are  very  rare,  however.  This  variety  of 
moon-stone  has  often  been  confounded  with  the  Oriental 
avanturine,  but  on  examination  may  at  once  be  detected. 


COMMON  FELSPJte.  315 

The  Ceylon  variety  ought  only  to  be  called  Oriental  moon- 
stone, from  the  peculiarity  that  it  is  more  uniform,  not 
striated  like  that  from  St.  Gothard,  and  having  also  a 
brighter  lustre;  its  chatoyant  qualities  are  therefore  more 
prominent. 

Sun-stone  contains  minute  scales  of  mica,  and  reflects  a 
pinchbeck-brown  tint. 

• 

COMMON   FELSPAE. 

This  felspar  occurs  in  crystals,  massive,  and  disseminated  ; 
its  fracture  is  uneven  and  splintery ;  is  translucent ;  has  a 
pearly  and  vitreous  lustre ;  its  colors  are  white,  gray,  red, 
yellow,  and  green,  in  their  various  shades,  sometimes  with 
a  variegated  bluish,  greenish,  or  reddish  play  of  colors ;  its 
texture  is  compact,  or  minutely  foliated. 

The  amazon-stone,  or  green  felspar,  is  from  Siberia ;  like- 
wise splendid  grass-green  felspar  has  been  found  in  the  Uni- 
ted States,  at  Southbridge  and  Hingham,  Massachusetts,  and 
Cow  Bay,  New  York;  of  apple-green  color,  at  Topsham, 
and  near  Baltimore,  Maryland.  Also,  the  American  glassy 
or  vitreous  felspar,  found  in  Delaware,  which  ought  prop- 
erly to  be  quoted  as  a  distinct  species,  is  arranged  with  this 
variety. 

Felspar  is  widely  diffused  all  over  the  globe,  and  with  a 
few  exceptions  is  more  common  than  any  other  mineral ;  it 
forms  a  constituent  part  of  most  primitive  rocks,  such  as 
gneiss,  granite,  &c. ;  is  the  principal  ingredient  of  the 
sienites,  porphyry,  and,  in  fact,  with  a  small  percentage  of 
other  minerals,  forms  whole  mountain  ranges  and  chains  in 
various  parts  of  the  globe :  such  we  see  in  Siberia,  the  north 
and  west  of  Scotland,  &c.,  all  of  which  are  surrounded  by 
felspar.  Immense  beds  exist  in  the  United  States :  around 
Wilmington,  in  the  State  of  Delaware,  is  an  inexhaustible 
deposit  of  exquisite  and  perfectly  pure  felspar;  and  ID 


316  A   POPU1*E   TREATISE    ON    GEMS. 

Connecticut  and  on  the  North  River  we  see  beds  of  the 
foliated  felspar  extending  for  miles.  Sweden,  Norway,  and 
Greenland  are  likewise  great  depositories  of  the  common 
felspar. 

The  amazon-stone  is  used  in  jewelry  for  rings,  pins, 
seals,  snuff-boxes,  &c.  It  is  principally  cut  at  Ekaterinen- 
burg,  Siberia,  where  it  is  ground  on  a  leaden  wheel  with 
emery,  and  polished  with* rotten-stone  on  a  wooden  wheel; 
its  form  is  that  of  cabochon,  and  sometimes  that  of  the 
mixed  pavilion-cut,  when  the  table  is  to  be  cut  pretty  large, 
and  arched,  in  order  to  display  more  distinctly  its  peculiar 
colors. 

Common  felspar  is  of  no  great  value,  and .  only  the  ama- 
zon-stone is  used  in  jewelry,  which  commands  a  good 
price.  Cut  specimens,  suitable  for  ear-rings  or  brooches, 
are  worth  from  three  to  five  dollars. 

A  very  fine  specimen  of  the  amazon-stone,  in  its  rough 
state,  may  be  seen  in  the  New  York  Lyceum  of  Natural 
History.  The  imperial  cabinet  of  St;  Petersburg  possesses 
two  vases  of  this  stone,  which  are  nine  inches  high  and  five 
and  one  half  inches  in  diameter.  Although  our  vitreous 
felspar  has  not  yet  been  brought  into  use  for  the  purposes 
of  jewelry  and  other  ornaments,  yet  it  bids  fair  to  con- 
tribute, at  one  day,  much  to  the  national  wealth  of  this 
country,  for  it  is  the  best  material  for  porcelain,  china,  and 
earthen-ware.  Already  have  many  cargoes  of  this  beautiful 
mineral  been  shipped  to  France  and  England  (six  hundred 
tons  of  the  Connecticut,  Middletown,  felspar  were,  accord- 
ing to  Professor  Shephard,  last  year  shipped  to  Liverpool, 
and  one  hundred  tons  to  the  Jersey  porcelain  manufactory), 
where  the  manufacturer  appears  to  appreciate  better  the 
purity  of  ingredients  for  the  purposes  just  mentioned.  In- 
stead of  receiving,  as  hitherto,  the  manufactured  goods 
from  abroad,  made  of  our  own  raw  material,  it  is  earnestly 


LABRADOR.  317 

to  be  hoped  that  w»  will  shortly  acquire  skill,  and  exert 
sufficient  industry  to  compete  with  loreign  manufacturers 
in  the  art  of  making  porcelain,  with  the  superior  material 
which  nature  has  so  abundantly  lavished  on  this  continent. 
I  possess  a  splendid  slab  of  the  vitreous  felspar,  of  one 
square  foot,  free  from  any  admixture,  and  imposing  in 
appearance. 

LABRADOR. 

This  mineral  was  heretofore  considered  as  a  variety  of 
felspar;  but  it  has  latterly  been  separated  from  it,  and 
ought,  therefore,  no  more  to  be  called  labrador  felspar,  the 
name  by  which  it  is  known  in  all  mineralogical  works. 

Labrador  was  first  discovered  by  the  Moravian  mission- 
aries on  the  island  of  St.  Paul,  on  the  coast  of  Labrador; 
and,  according  to  others,  by  Bishop  Launitz,  in  1775, 
when  it  was  first  brought  to  Europe.  Labrador  occurs  in 
crystalline  masses,  massive,  and  in  boulders;  it  is  of  an 
uneven  and  conchoidal  fracture ;  its  lustre  is  vitreous,  and 
in  one  direction  pearly;  it  is  translucent;  its  colors  are 
gray,  with  its  various  shades,  such  as  blackish  or  whitish- 
•  gray,  with  spots  of  an  opalescent  or  iridescent  vivid  play  of 
colors,  consisting  of  blue,  red,  green,  brown,  yellow,  or 
orange,  according  to  the  direction  in  which  light  is  falling 
upon  the  specimen ;  sometimes  several  of  these  colors  arje 
perceptible  at  the  same  instant,  but  more  commonly  they 
appear  in  succession  as  the  mineral  is  turned  towards  the 
light.  These  colors  are  said  to  originate  in  fissures  which 
intersect  the  texture  of  the  mineral,  as  they  are  only  per- 
ceptible from  that  side  where  they  fall  together  with  the 
foliated  structure,  and  not  like  the  opal,  whose  mass  is  sup- 
plied with  fissures  running  in  all  directions. 

Labrador  scratches  white  glass,  is?  scratched  by  rock- 
crystal,  and  is  somewhat  less  hard  than  felspar ;  its  specific 


318  A  POPULAB  TREATISE  ON  GEMS. 

gravity  is  2'7l  to  2'75 ;  before  the  blowpipe  it  fuses  with 
difficulty,  and  is  said  to  lose  its  play  of  colors ;  it  consists 
of  silex,  alumina,  lime,  soda,  with  some  oxide  of  iron  and 
water.  Labrador  is  found  as  a  rock  and  boulder,  in  St. 
Petersburg,  Norway,  Bohemia,  Saxony,  Sweden,  St.  Paul's 
Island  on  the  coast  of  Labrador,  and  in  the  United  States, 
in  Essex  county  (New  Jersey),  at  the  mouth  of  the  North 
River,  and  near  Lake  Champlain,  New  York,  where, 
according  to  the  description  given  me  by  Archibald  Mc- 
Intyre,  Esq.,  its  splendid  colors  are  seen  on  both  sides  of 
the  water,  but  a  few  yards  apart,  and  the  effect  of  the  rays 
of  the  morning  sun  falling  upon  the  rock  and  water  at  the 
same  time,  is  said  to  equal  that  of  the  prismatic  spectrum 
thrown  into  a  dark  room. 

Labrador  is  used  for  rings,  pins,  buttons,  snuff-boxes, 
letter-holders,  cane-heads,  and  other  ornaments,  such  as 
vases  and  larger  articles;  but  care  has  to  be  taken  in 
grinding,  that  the  direction  where  the  *play  of  colors  is 
visible  is  kept  straight,  and  that  it  is  cut  in  cabochon. 
The  price  of  labrador  is  not  very  high,  but  soon  after  its 
discovery,  a  Doctor  Anderson,  having  described  the  min- 
eral as  displaying  all  the  variegated  tints  of  color  that  are 
to  be  seen  in  the  plumage  of  the  peacock,  pigeon,  or  most 
delicate  humming-bird,  and  specimens  having  been  carried 
to  England,  so  great  was  the  avidity  to  possess  it,  that 
small  pieces  were  sold  for  twenty  pounds  sterling.  The 
present  price  of  good  specimens  is  from  two  to  ten  dollars ; 
and  a  few  years  ago  I  purchased  some  letter-holders,  which 
are  beautiful  specimens,  for  which  I  paid  four  dollars 
each.  The  largest  specimens  of  labrador  are  in  the  col- 
lection of  the  Minerajogical  Society,  and  in  the  museum  of 
the  Academy  of  Sciences  at  St.  Petersburgh,  which  were 
found  on  the  shore  of  the  Pulkouka  j  one  of  them  weighs 
(en  thousand  pounds.  I  have  in  my  possession  a  rough 


LABEADOE.  319 

specimen  of  the  labrador  of  this  State,  merely  rubbed  off 
on  the  surface,  and  its  colors,  I  venture  to  say,  equal,  if 
they  do  not  indeed  excel,  in  every  respect,  those  of  the 
specimens  from  St.  Paul's  Island ;  and  I  anticipate  the  day 
when  the  citizens  of  New  York  will  take  as  much  pride  in 
possessing  labrador  table  and  mantel  slabs,  as  they  now  do 
in  employing  the  Italian  and  Irish  marble  for  these  pur- 
poses ;  for  the  resources  appear  to  be  inexhaustible  in  the 
rocky  county  of  Essex.  We  do  not  see  many  specimens 
brought  from  the  coast  of  Labrador,  and  I  was  informed 
by  Mr.  Audubon,  on  his  return  from  that  quarter,  that  he 
could  not  find  any  specimens.  Mr.  Henderson,  of  Jersey 
City,  who  presented  me  the  above-mentioned  rough  speci- 
men, had  likewise  splendid  small  polished  specimens  in 
breastpins,  displaying  all  the  properties  in  their  full  beauty. 
The  same  gentleman,  who  travelled  last  summer  in  com- 
pany with  several  scientific  State  geologists,  mentions  that 
they  picked  up  beautiful  specimens  at  the  height  of  five 
thousand  seven  hundred  feet  above  the  level  of  the 
sea. 

In  the  collection  of  Columbia  College  is  a  fine  specimen 
of  labrador,  brought  from  Gaspe,  Lower  Canada,  by  the 
Hon.  Mrs.  Percival. 

In  1799,  it  was  announced"  that  in  Russia*  a  labrador  spar 
was  discovered,  where  a  perfect  drawing  and  image  of 
Louis  XVI.  could  be  distinctly  traced,  his  head  surrounded 
by  a  colored  crown  of  pomegranate,  with  a  rainbow  border, 
and  a  silvery  plume  of  azure  color ;  it  was  what  may  be 
called  a  lusus  naturae.  Count  de  Robassome,  .formerly 
in  the  Russian  service,  was  the  possessor  of  this  singular 
stone,  and  he  demanded  for  the  same,  the  sum  of  250,000 
francs. 

There  were  some  magnificent  specimens,  tables,  and 
other  ornaments,  in  the  London  Exhibition. 


320  A   POPULAR   TREATISE   ON   GEMS.* 

In  the  New  York  Exhibition,  were  likewise  fine  speci 
mens  exhibited  from  Labrador  and  the  New  York  locality. 


HYPERSTHENE. 

This  mineral  was  formerly  annexed  to  hornblende,  but 
has  latterly  been  separated ;  its  name  is  derived  from  the 
Greek,  and  means  of  superior  strength,  in  reference  to 
the  great  hardness  and  specific  gravity  which  it  possesses. 

Hypersthene  is  found  in  crystalline  masses ;  it  has  an  un- 
even fracture ;  it  is  opaque,  and  its  colors  are  dark-brown, 
red,  and  greenish  or  grayish  black ;  the  cleavage  is  parallel 
to  the  sides,  and  shorter  diagonals  of  a  rhombic  prism  ;  its 
lustre  is  metallic,  and  when  viewed  in  one  certain  direction, 
copper-red,  light-brown,  or  gold-yellow,  and  in  others  it 
has  a  greenish  play  of  colors.  It  scratches  glass,  has  a 
darkish-green  streak-powder,  and  has  a  specific  gravity  of 
3'38 ;  it  is  easily  fusible  before  the  blowpipe  on  charcoal 
into  a  grayish-dark  bead ;  acids  have  no  effect  upon  it ;  it 
consists  of  magnesia,  silex,  alumina,  and  lime,  with  some 
water. 

It  is  found  forming  a  constituent  of  the  labrador  rock, 
on  the  coast  of  Labrador,  Greenland,  and  in  the  United 
States,  on  Brandywine  creek  in  Pennsylvania,  and  in  Essex 
county,  New  Jersey;  fine  specimens  have  been  found  in 
Hingham,  Massachusetts.  The  French  jewellers  have  lately 
begun  to  introduce  this  mineral  for  rings,  pins,  and  other 
ornaments,  on  account  of  its  high  polish  and  beautiful 
color.  The  best-colored  pieces  are  cut  out  of  the  mass, 
and  ground  on  a  lead  wheel  with  emery  in  cabochon,  and 
polished  with  rotten-stone.  Beauty  of  color  and  other 
qualifications  determine  the  price  of  this  stone ;  at  Paris  a 
hypersthene,  in  cabochon  cut,  eight  to  ten  lines  long  and 
six  lines  broad,  was  sold  for  one  hundred  and  twenty  francs. 


IDOCEASE.  321 

The  mineral  is,  however,  pretty  rare,  and  has  not  yet 
been  fully  introduced. 


EDOCEASE. 

0 

This  mineral  occurs  mostly  crystallized,  in  the  form  of  a 
four-sided  prism,  terminated  by  four-sided  pyramids ;  also, 
massive ;  its  cleavage  is  parallel  to  all  the  planes  of  the 
prism ;  it  is  transparent  and  opaque ;  possesses  strong 
double  refraction  of  light ;  its  lustre  is  between  vitreous 
and  resinous ;  its  cross  fracture  conchoidal ;  the  crystals 
are  all  striated  in  length ;  its  colors  are  •yellowish  or 
brownish  green,  orange-yellow,  sometimes  blue  and  black. 
It  scratches  white  glass  and  felspar,  but  is  scratched  by 
topaz.  Its  streak-powder  is  white,  and  it  has  a  specific 
gravity  of  3 '8  to  3*4.  Before  the  blowpipe,  it  is  fusible 
into  a  brownish  glass.  It  consists  of  lime,  alumina,  silex, 
with  some  oxide  of  iron  and  manganese. 

Idocrase  is  found  •  in  different  geological  positions  in 
primitive  and  volcanic  rocks,  in  the  cavities  of  the  serpen- 
tine in  the  Alps,  in  Piedmont,  Mount  Soinma,  Vesuvius, 
Etna ;  also,  Norway,  Sweden,  Spam ;  in  the  United  States, 
at  Worcester,  Massachusetts;  Salisbury,  Connecticut ;  Cum- 
berland, Rhode  Island. 

Idocrase,  of  pure  green  and  brown  colors,  and  transpar- 
ent, is  used  for  rings  and  pins,  and  at  Naples  and  Turin, 
it  is  principally  cut  for  jewelry  on  a  leaden  wheel,  and  is 
polished  on  wood  with  pumice-stone.  The  forms  it  receives 
are  the  brilliant,  table,  and  pavilion,  and  if  perfectly  pure, 
is  mounted  d  jour ;  otherwise  with  a  suitable  foil.  The 
price  of  idocrase  is  not  very  high,  as  it  is  but  little  known 
among  jewellers. 

Chrysolite  and  the  green  garnet  are  often  substituted  for 

idocrase ;  but  the  first  has  a  greater  specific  gravity  and  is 

HO 


322  A  POPULAR  TEEATISE   ON   GEMS. 

of  a  more  vivid  color  ;  the  latter  is  harder,  and  likewise  of 
greater  specific  gravity. 

The  Italian  ido  erase,  which  is  cut  at  Naples,  is  mostly 
called  the  Italian  chrysolite. 


HAUYNE. 

The  name  of  this  mineral  was  given  in  honor  of  the 
celebrated  French  mineralogist,  the  Abbe  Hatiy.  It  occurs 
in  dodecahedral  crystals,  with  brilliant  faces  ;  also,  in  grains 
and  massive  ;  it  has  a  conchoidal  fracture  ;  is  transparent 
and  translucent  ;  possesses  a  strong  vitreous  lustre  ;  its 
structure  is  imperfectly  foliated.  Its  colors  are  indigo,  sky, 
and  smalt  blue  ;  also,  white,  green,  gray,  and  black.  It 
scratches  white  glass  and  is  scratched  by  quartz;  white 
streak-powder;  specific  gravity  is  2*47.  Before  the  blow- 
pipe it  loses  its  color  and  fuses  into  a  porous  glass,  and  with 
borax  into  a  diaphanous  glass,  which  turns  yellow  on  cool- 
ing; it  forms  a  jelly  with  acids.  ,  It  consists  of  lime, 
alumina,  silex,  protoxide  of  iron,  sulphuric  acid,  and  soda 
or  potash. 

It  is  found  in  slacked  basalt,  and  ejections  of  Mount  Ve- 
suvius ;  on  Bodenmaise,  on  the  Laach  Lake,  in  Italy,  and 
on  the  island  of  Tiree,  Scotland. 

Hatiyne  is  not  much  known  yet,  but  has  lately  been 
used  for  rings,  ear-rings,  brooches,  &c.  ;  it  is  cut  like  ido- 
crase,  but  the  price  will  always  be  high  on  account  of  its 
scarcity. 

LAPIS   LAZULI. 

The  name  of  this  mineral  is  derived  from  the  Persian 
language,  and  means  blue  color,  or,  with  the  Latin  prefix, 
blue  stone.  The  ancients  were  well  acquainted  with  it, 
and  have  employed  it  as  a  substitute  for  other  gems.  The 


LAPIS   LAZULI.  .323 

Greeks  and  Romans  are  said  to  have  called  it  by  the  name 
of  sapphire,  denominating  that  with  specks  of  iron  pyrites 
the  sapphirus  regilus  /  Pliny  called  it  the  cyanus.  It  was 
formerly  used  as  a  strengthening  medicine. 

Lapis  lazuli  very  seldom  occurs  crystallized ;  its  regu- 
lar form  is  the  oblique  four-sided  prism ;  it  mostly  occurs 
compact,  and  in  grains  and  specks,  with  an  uneven  and 
conchoidal  fracture;  it  is  translucent  on  the  edges;  its 
lustre  is  nearly  vitreous  and  shining ;  structure  foliated  ;  its 
color  is  fine  azure-blue,  with  different  shades,  often  inter- 
spersed with  spots  and  veins  of  pyrites.  It  scratches  glass, 
but  is  attacked  by  quartz  and  by  the  file ;  its  specific 
gravity  is  2'3  ;  before  the  blowpipe  and  on  charcoal  it  with 
difficulty  runs  into  a  white  glass,  but  with  borax  it  fuses 
with  effervescence  into  a  limpid  glass.  It  consists  of  lime, 
magnesia,  alumina,  and  silex,  with  soda,  protoxide  of  iron, 
and  sulphuric  acid. 

It  is  generally  called  in  trade,  the  Armenian-stone. 

It  is  found  in  gangues  of  the  older  formations,  and  in 
Bucharia ;  it  exists  in  granite  rocks,  and  is  disseminated 
in  all  veins  of  thin  capacity ;  on  the  Baikal  Lake  it  is  found 
in  solid  pieces;  also,  in  Siberia,  Thibet,  China,  Chili,  and 
Great  Bucharia. 

Lapis  lazuli  is  much  used  for  jewelry,  such  as  rings, 
pins,  crosses,  ear-rings,  &c.  The  best  pieces  are  generally 
cut  out  from  larger  lumps  by  means  of  copper  saws  and 
emery,  then  ground  with  emery  on  a  lead  wheel,  and 
polished  with  rotten-stone  on  a  tin  wheel.  The  rocks 
which  yield  lapis  lazuli,  where  it  is  contained  in  specks, 
are  likewise  cut  for  ornamental  purposes,  such  as  snuff- 
boxes, vases,  candlesticksr  cups,  columns,  cane-heads,  &c. ; 
also,  for  architectural  ornaments  and  stone  mosaic;  the 
larger  specimens,  having  specks  regularly  disseminated  on 
a  white  ground  of  the  rock,  are  those  selected  for  cutting. 


324  A  POPULAR  TREATISE  ON  GEMS. 

The  most  important  use  of  this  mineral  is  that  of  furnish- 
ing the  celebrated  and  beautiful  pigment  called  ultramarine- 
blue,  used  by  painters  in  oil,  and  said  never  to  fade.  The 
lapis  lazuli  takes  a  very  high  polish,  but  becomes  dull  again 
after  being  used  for  some  time.  It  is  sometimes  imitated 
by  lazulite' (azure-stone),  or  blue  carbonate  of  copper,  which, 
however,  is  not  near  so  hard,  and  -effervesces-  on  testing 
with  nitric  acid.  Those  specimens  having  iron  pyrites 
inclosed  are  difficult  to  polish  well,  on  account  of  the  un- 
equal hardness  of  the  two  minerals. 

Lapis  lazuli  has  latterly  been  discovered  in  California, 
but  the  color  of  the  mineral  from  this  locality  is  very  in- 
different, and  its  price  is  therefore  much  inferior  to  that 
from  Persia.  In  Paris,  the  price  is  estimated  at  300  francs 
per  kilogramme.  There  are  many  engravings  in  lapis 
lazuli,  such,  for  instance,  as  the  Emblem  of  Peace — a  figure 
with  a  torch  in  one  hand  and  a  cornucopia  in  the  other,  and 
appearing  to  embrace  military  trophies,  placed  before  her. 

The  Chevalier  d'Azara,  Spanish  minister  in  France,  pos- 
sessed while  there  a  very  beautiful  cameo  of  lapis  lazuli, 
representing  the  head  of  Medusa,  but  without  serpents. 
Maffei  speaks  of  a  Venus  being  carried  by  a  she  goat 
whipped  by  Love. 

The  French  crown-jewels  contained  some  fine  and  gigan- 
tic specimens  of  lapis  lazuli :  one  in  the  form  of  a  boat  of 
large  dimensions,  valued  at  200,000  francs ;  a  sabre-handle 
given  to  Louis  XVI.,  by  Tippoo-Saib,  valued  at  6000 
francs  ;  a  large  vase,  valued  at  2600  francs. 

In  1855,  at  the  Paris  Exhibition,  were  numerous  objects 
and  carvings,  exhibited  by  Rudolphi,  which  fairly  compared 
with  the  antique  relics  of  this  species,  both  in  material  and 
in  taste  of  execution. 

A  marine  shell  carved  from  lapis  lazuli  was  beautifully 
mounted  by  Morrel,  and  another  chefcPoeuvre,  in  lapis  lazuli, 


LAPIS  LAZULI.  325 

by  Duponchel.     A  small  round  table  of  mosaic  and  lapis 
lazuli,  which  was  a  beautiful  work  by  Jarry. 

A  magnificent  bagnivola  of  lapis  lazuli,  of  very  large  size, 
and  extremely  pure  and  rich  in  color,  was  exhibited  by  Mr. 
Jones,  in  the  London  Exhibition,  in  1851. 

Lapis  lazuli  has  been  well  imitated  of  late,  and,  but  for 
the  touch,  with  much  difficulty  to  be  distinguished  from 
the  genuine,  it  is  manufactured  from  bone-ashes  and  oxide 
of  cobalt. 

The  value  of  lapis  lazuli,  although  depending  upon  its 
purity,  intensity  of  color,  and  size,  has  nevertheless  much 
diminished  when  compared  with  its  former  prices. 
.  The  Chinese,  who  have  for  a  long  time  employed  lapis 
lazuli  in  their  porcelain  painting,  call  the  pure  and  sky- 
blue  stone  zuisang,  and  the  dark-blue,  with  disseminated 
iron  pyrites,  the  tchingtchang,  preferring  the  latter  to  the 
former ;  they  work  the  same  for  many  ornaments,  such  as 
vases,  snuff-boxes,  buttons,  and  cups. 

In  the  palace  which  Catharine  II.  built  for  her  favorite, 
Orlof,  at  St.  Petersburg,  there  are  some  apartments  entirely 
lined  with  lapis  lazuli,  which  forms  a  most  magnificent  deco- 
ration. I  have  several  slabs,  three  inches  long,  and  of  fine 
azure-blue  color,  in  my  possession. 

The  production  of  ultramarine  has  been  known  since  1502, 
and  was  already  employed,  under  the  name  of  azurum  ul- 
tramarinwtn,  by  Camillas  Leonarus. 

The  process  of  preparing  ultramarine  was  known  as 
early  as  the  fifteenth  century.  The  color  is  now  mostly 
prepared  at  Rome,  in  the  following  manner :  those  pieces 
which  are  free  from  pyrites  specks,  are  first  calcined  and 
pulverized  ;  the  powder  is  then  formed  into  a  mass  with  a 
resinous  cement  (pastello),  and  fused  at  a  strong  heat ;  this 
is  then  worked  with  the  hands  in  soft  water,  whereby  the 
finest  coloring  particles  are  disengaged  in  the  water, 


326          A  POPULAR  TBEATISE  ON  GEMS. 

which  will  soon  be  impregnated  with  the  blue  color ;  a  fresh 
portion  of  water  is  then  taken,  and  the  same  operation  is 
continued  until  the  remains  are  colorless.  The  ultramarine, 
after  a  short  time,  settles  to  the  bottom  of  the  vessels,  and 
is  carefully  separated  and  dried.  If  the  lapis  lazuli  be  of 
the  best  quality,  the  product  will  be  from  two  to  three  per 
cent.  That  color  which  remains  yet  in  the  mass  is  of  an 
inferior  quality,  and  is  called  the  ultramarine  ashes ;  it  is 
of  a  paler  and  more  reddish  color. 

Good  ultramarine  has  a  silky  touch,  and  its  specific  gravity 
is  2*36.  It  does  not  lose  its  color  if  exposed  to  heat,  but  is 
soon  discolored  by  acids,  and  forms  a  jelly.  In  order  to 
distinguish  the  pure  ultramarine  from  numerous  spurious 
and  adulterating  coloring  materials,  such  as  indigo,  Prus- 
sian-blue, mineral-blue,  <fcc.,  it  is  only  necessary  to  test  the 
article  in  question  with  some  acid,  when  after  a  few  minutes 
the  real  ultramarine  is  discolored,  yielding  a  clear  solution 
and  a  white  residuum.  The  real  ultramarine  has  always 
been  at  a  very  high  price,  on  account  of  the  small  product 
obtained  from  the  mineral.  An  ounce  of  the  purest  ultra- 
marine is  sold  in  France  for  two  hundred  to  two  hundred 
and  fifty  francs,  which  is  not  within  the  reach  of  all  painters. 

In  the  year  1828,  the  discovery  was  made  by  Professor 
Gmelin,  in  Tubingen,  that  sulphuret  of  soda  was  the  proper 
material  for  imitating  this  precious  and  valuable  pigment. 
By  his  experiments  he  succeeded  in  preparing  this  substance 
from  silex,  alumina,  soda,  and  sulphur,  producing  a  color 
in  every  respect  corresponding  with  the  true  color  of  the 
lapis  lazuli,  and  bearing  the  same  relation  to  acids  as  the 
genuine  ultramarine.  This,  for  econovny,  has  become  a 
great  object  to  painters  and  color-men,  since  a  whole  pound 
of  it  may  be  purchased  in  France  for  twenty  francs.  As  it 
bids  fair  to  meet  with  a  great  consumption,  being  even 
substituted  for  cobalt  in  bluing  paper,  thread,  and  other 


KTAJHTE.  327 

stuffs,  several  manufacturers  have  already  been  induced  to 
engage  largely  in  its  preparation;  and  there  is  now  a  very 
extensive  establishment  in  full  operation  by  M.  Guimet, 
three  leagues  from  Lyons,  who  likewise  claims  the  priority 
of  its  discovery:  the  royal  porcelain  manufactory  at  Meissen, 
in  Saxony,  also  prepares  it.  The  process"  for  making  the 
artificial  ultramarine,  as  it  was  first  described  by  Gmelin,  is 
here  given,  as  it  was  published  in  the  Annales  de  Chimie. 
The  whole  process  is  divided  into  three  parts-: 

1.  The  pure  hydrate  of  silica  is  prepared  by  fusing  fine 
pulverized  quartz  or  pure  sand  with  four  times  its  own 
weight  of  salt  of  tartar,  dissolving  the  fused  mass  in  water 
and  "precipitating  by  muriatic  acid ;   also  the  hydrate  of 
alumina  is  prepared  from  alum  in  solution,  precipitated  by 
ammonia. 

2.  Dissolve  the  silex  so  obtained  in  a  hot  solution  of 
caustic  soda,  and  add  to  seventy  parts  of  the  pure  silex 
seventy-two  parts  of  alumina;  then  evaporate  these  sub- 
stances until  a  moist  powder  remains. 

3.  In  a  covered  Hessian  crucible,  a  mixture  of  dried  sal 
soda,  one  part  to  two  parts  of  sulphur,  is  heated  gradually, 
until  it  is  fully  fused,  and  to  the  fused  mass  add  small 
quantities  of  the  earthy  precipitate,  taking  care  not  to 
throw  in  fresh  quantities  until  all  the  vapors  have  ceased ; 
after  standing  for  an  hour  in  the  fire,  remove  the  crucible, 
and  allow  it  to  cool.     It  now  contains  the  ultramarine, 
mixed  with  an  excess  of  sulphuret,  which  is  to  be  removed 
by  levigation ;  and  if  the  sulphuret  is  still  in  excess,  it  is 
to  be  expelled  by  moderate  heat.     Should  the  color  not  be 
uniform,  levigation  is  the  only  remedy 

KYANTTE,    SAPPAEE,    DISTHENH. 

The  name  of  this  mineral  is  derived  from  the  Greek, 
signifying  blue,  and  was  given  to  it  on  account  of  its  blue 


828  A  POPULAR  TREATISE  ON  GEMS. 

cc^or.  It  has  been  known  for  many  centuries,  having  been 
cut  by  a  Gernlan  lapidary,  Cornellius,  in  the  reign  of  James 
I.,  under  the  name  of  sappare,  by  which  it  is  yet  known 
among  the  French  jewellers. 

It  occurs  in  masses  composed  of  a  confused  aggregation 
of  crystals,  and  in  distinct  crystals  of  four  or  eight  sided 
prisms,  much  compressed,  with  two  broad  shining  faces. 
The  crystals  are  generally  closely  aggregated,  and  are  cross- 
ing or  standing  on  each  other  in  a  hemitropic  form,  so  as 
to  present  a  singular  and  curious  aspect.  Some  of  the 
crystals  are  curved,  others  are  corrugated  or  wrinkled,  as 
though  they  had  been  pressed  endwise,  or  had  not  room 
to  stretch  themselves  at  full  length ;  others  are  pressed  into 
triangular  shapes,  &c.  It  has  a  foliated  structure ;  uneven 
fracture ;  is  transparent  and  translucent ;  possesses  simple 
refraction  of  light ;  its  lustre  is  vitreous  and  pearly ;  its 
colors  are  azure-blue,  passing  into  light-blue  or  bluish- white 
and  bluish-green.  It  scratches  white  glass,  and  is  attacked 
by  topaz  or  a  good  file  ;  yields  a  white  streak-powder ;  has 
a  specific  gravity  of  3*63  to  3*67.  It  becomes  electric  by 
rubbing,  and  often  exhibits  positive  and  negative  electricity 
in  one  and  the  same  specimen;  it  is  infusible  before  the 
blowpipe,  but,  with  borax,  fuses  with  difficulty  into  a  trans- 
parent limpid  glass :  acids  have  no  effect  upon  it. 

It  consists  of  alumina  and  silex,  sometimes  combined 
with  oxide  of  iron  and  water. 

The  kyanite  is  found  in  micaceous,  talcose,  and  argilla- 
ceous slate,  at  St.  Gothard,  in  the  Tyrol,  and  in  Switzer- 
land; in  Styria,  Carinthia,  Bohemia,  Spain,  and  Siberia; 
also,  in  the  United  States,  of  the  purest  azure-blue  color : 
large  specimens  in  Litchfield,  Haddam,  and  near  New 
Haven  (Connecticut) ;  Chesterfield,  Conway,  Granville, 
Deerfield,  and  Plainfield  (Massachusetts) ;  Grafton,  Nor- 
wich, and  Bellows  Falls  (Vermont)  ;  Oxford  (New  Hamp- 


TURQUOISE.  329 

shire) ;  East  Bradford,  East  Marlborongh,  smd  Chester 
county  (Pennsylvania)  ;  likewise,  of  a  delicate  light-blue, 
variously  shaded,  in  Foster  (Rhode  Island). 

The  kyanite  has  not  yet  been  received  as  a  favorite 
among  the  jewellers  (perhaps  from  not  being  generally 
known  by. them),  or  else  it  would  long  since  have  been 
cut  for  various  ornamental  purposes,  more  particularly  in 
in  this  country,  where  the  localities  are  so  numerous  and 
the  color  so  beautiful.  When  well  cut,  it  may  be  substi- 
tuted for  the  sapphire.  I  indulge  the  hope  that  .some 
jewellers  or  lapidaries  may  take  a  hint  from  4his  remark. 
In  France  and  Spain,  it  has  for  some  years  past  been  used 
for  rings,  brooches,  and  other  jewelry.  It  is  generally 
ground  with  emery  on  a  lead  wheel,  and  with  pumice-ston.e 
polished  on  a  wood  plate,  receiving  the  last  polish  with 
rotten-stone.  The  form  it  receives  is  cabochon  or  table 
cut.  Usually,  the  best  parts  of  good  uniform  colored  speci- 
mens are  picked  out  for  cutting* 

The  price  of  this  stone  depends  upon  the  hardness,  color, 
and  polish :  perfect  specimens  command  a  good  price. 
Very  fine  cut  specimens  are  brought  from  the  East  Indies, 
and  sold  in  France  as  sapphires. 


TURQUOISE. 

The  name  of  this  mineral  is  probably  derived  from  the 
country  whence  it  was  generally  brought  into  market, 
which  is  Turkey.  In  ancient  times  it  was  used  as  a  remedy 
for  several  diseases,  and- was  also  worn  as  an  amulet  against 
disasters.  It  occurs  in  reniform  masses  and  in  specks; 
has  a  conchoidal  fracture  ;  is  opaque ;  of  a  dull  and  waxy 
lustre ;  its  colors  are  blue  and  green,  from  sky-blue  to 
apple-green,  sometimes  yellowish  ;  it  scratches  apatite,  but 
not  quartz  nor  white  glass,  and  is  easily  attacked  by  the 


330  A  POPULAR  TREATISE  ON  GEMS. 

file ;  it  has  a  white  streak-powder ;  its  specific  gravity  is 
2'86  to  3*0; "it  is  infusible  before  the  blowpipe  alone,  but 
loses  its  blue  color .  and  becomes  yellowish-brown ;  but  it 
fuses  with  borax  into  a  limpid  glass.  Muriatic  acid  has  no 
effect  upon  it.  Consists  of  alumina,  phosphoric  acid,  water, 
oxide  of  copper,  and  protoxide  of  iron. 

There  are  two  kinds  of  turquoise  used  in  trade,  which 
differ  materially  in  their  composition,  and  are  from  differ- 
ent localities : 

1.  Turquoise  from  the  old  rock,  or  true  turquoise,  which 
is  generally .  called    Oriental  turquoise,  we   receive  from 
Persia,  and  is  of  a  sky-blue  and  greenish  color. 

2.  Turquoise  from  the  new  rock,  the  occidental  or  bone 
and  tooth  turquoise,  which  is  either  dark-blue,  light-blue, 
or  bluish-green ;  the  surface  of  this  mineral  is  sometimes 
traversed  by  veins  which  are  lighter  than  the  ground ;  it  is 
of  organic  origin,  consisting,  probably  of  colored  teeth  of 
antediluvian  animals  ;  it  owes  its  color,  according  to  Bouil- 

.  '  .  '  O 

Ion  Lagrange,  to  two  per  cent,  of  phosphate  of  iron,  which 
is  contained  in  it.  It  is  easily  distinguished  from  Oriental 
turquoise  by  its  structure,  internally  foliated  and  striated, 
which  is  an  indication  of  a  bony  composition ;  it  does  not 
take  so  high  a  polish,  is  discolored  in  distilled  water,  dis- 
solves in  acids,  and  is  totally  destroyed  by  aquafortis.  Its 
localities  are  Siberia,  Languedoc  in  France,  and  other 
places. 

True  or  Oriental  turqupise  is  found  in  small  gangues  of 
bog-ore  and  silicious  schist,  in  boulders,  &c.  A  mineral 
by  the  name  of  kalaite,  occurring  as  a  coating  to  silicious 
sinter,  in  Silesia  and  Saxony,  was  some  years  ago  dis- 
covered. Turquoise  is  brought  to  market  by  the  mer- 
chants, of  Bucharia,  ready  cut  and  polished;  and  in  Mos- 
cow'it  is  wrought  over,  being  ground  on  a  lead  wheel  with 
emery,  and  polished  with  rotten-stone  or  pumice-stone  on  a 


TURQUOISE.  331 

tin  wheel ;  and  its  last  and  best  polish  is  received  from  the 
jewellers,  by  rubbing  with  a  linen  rag  and  rouge.  Since  it 
is  often  traversed  by  fissures  and  cracks  in  the  interior, 
it  requires  great  caution  in  grinding.  It  is  mostly  cut  in 
the  form  of  cabochon  ;  also,  as  thick  or  table  stones,  and  is 
used  for  numerous  purposes  in  jewelry,  such  as  rings,  ear- 
rings, brooches,  and  also  for  mounting  around  the  most 
precious  gems. 

The  price  of  turquoise  has,  for  the  last  ten  years,  much 
decreased ;  that  of  an  Oriental  is  generally  four  times 
higher  than  the  occidental:  one  the  size  of  a  pea  is  worth 
about  five  dollars;  a  good  turquoise,  sky-blue  and  oval-cut, 
five  lines  long  and  four  and  a  half  lines  broad,  was  sold  in 
France  for  two  hundred  and  forty-one  francs ;  and  a  light- 
blue,  greenish  lustre,  and  oval-cut,  five  and  a  half  lines  long 
and  five  broad,  was  sold  for  five  hundred  francs ;  whereas 
an  occidental  turquoise,  four  lines  long  and  three  and  a  half 
broad,  brought  only  one  hundred  and  twenty-one  francs. 
Turquoise  is  very  well  imitated  artificially  (so  much  so  as  to 
render  it  difficult  to  discover  the  difference  between  that  and 
the  real),  by  adding  to  a  precipitated  solution  of  copper  and 
spirits  of  hartshorn,  finely-powdered  and  calcined  ivory- 
black,  and  leaving  the  precipitate  to  itself  for  about  a  week, 
at  a  moderate  heat,  and  afterwards  carefully  drying  the 
same,  and  exposing  to  a  gentle  heat.  This  artificial  tur- 
quoise is  softer  than  the  real,  and  cuts  with  a  knife  in 
shavings,  whereas  the  genuine  yields  a  white  powder.  The 
real  turquoise  displays  in  the  daytime  a  sky-blue,  and  at 
night  a  light  and  greenish  color ;  is  not  attacked  by  acids, 
and  resists  the  fire. 

In  the  museum  of  the  Imperial  Academy  at  Moscow,  is 
a  turquoise  more  than  three  inches  in  length  and  one  inch 
in  breadth. 

A  jeweller  at  Moscow  is  said  to  have  had  in  his  posses- 


332  A  POPULAR  TREATISE  ON  GEMS. 

sion  a  turquoise  two  inches  long,  in*  the  form  of  a  heart. 
This  formerly  belonged  to  Nadir  Shah,  who  wore  it  as  aE 
amulet,  for  which  he  asked  five  thousand  rabies. 

A  short  time  ago,  I  beheld,  at  a  sale,  one  of  the  largest 
and  most  splendid  turquoises,  which  was  one  inch  in  size, 
and  of  a  blue  color. 

Major  McDonald's  collection  of  turquoises,  from  Arabia, 
exhibited  at  the  London  Exhibition,  in  1851,  was  very 
beautiful ;  it  consisted  of  two  hundred  specimens,  cut  and 
polished.  They  differed  very  little  from  the  Persian  tur- 
quoises. He  discovered  several  localities  in  the  country  of 
Sonalby,  sixteen  days'  journey  northeast  of  Suez,  but  all 
were  within  a  range  of  forty  miles,  and  upon  a  mountain 
range,  at  from  five  thousand  to  six  thousand  feet  of  eleva- 
tion. Some  turquoises  were  found  in  situ,  but  most  of  them 
were  collected  from  the  ravines  descending  the  mountain 
chain.  The  rock  is  a  reddish  sandstone,  composed  of  quartz 
grains,  belonging  to  the  paleozoic  rocks.  Their  hardness 
is  equal  to  that  of  agate.  The  nodules  of  turquoise  form 
groups,  almost  like  currant  seeds,  in  the  sandstone.  There 
may  be  observed  in  this  collection,  veins  and  small  concre- 
tions from  one  tenth  to  one  twentieth  of  an  inch  in  thick- 
ness, which  cut  across  the  bed  of  sandstone  like  small 
threads ;  in  color  they  vary  from  an  intense  blue  to  a  bluish- 
white. 

NATROLITE. 

This  mineral  has  been  discovered  of -late  years,  and  re- 
ceives its  name  from  the  Latin  natron,  soda,  given  to  it  on 
account  of  that  alkali  being,  contained  in  it;  it  occurs  reni- 
form,  botryoidal,  and  massive,  such  as  mammillary,  and  in 
the  alternate  zones  around  the  centre;  it  has  a  splintery 
fracture;  is  translucent  on  the  edges;  of  a  pearly  lustre: 
its  colors  are  white,  yellowish-white,  or  reddish-brown,  and 


FLUOR    SPAR.  333 

they  often  alternate  in  different  layers ;  it  scarcely  scratches 
glass,  but  is  scratched  by  felspar;  has  a  white  streak- 
powder;  its  specific  gravity  is  2*16;  it  fuses  before  the 
blowpipe  into  a  colorless*  spongy  glass ;  it  consists  of  soda, 
alumina,  silex,  and  water,  sometimes  a  little  oxide  of  iron. 
Its  localities  are  Switzerland,  Bohemia,  Saxony,  Scotland, 
and  Nova  Scotia.  Natrolite,  on  abcount  of  its  suscepti- 
bility of  a  high  polish,  has  been  used  for  rings  and  other 
ornaments  in  jewelry,  but  has  not  yet  been  hi  much  de- 
mand, and  its  value  is  also  very  inconsiderable. 

FLUOR  SPAR. 

This  mineral  was  well  known  to  the  ancients,  but  did  not 
attract  particular  attention  until  the  sixteenth  century, 
when  it  was  introduced  as  a  flux.  As  early  as  1670,  the  art 
of  etching  on  glass  by  means  of  fluor  spar  was  practised  at 
Nuremberg. 

Fluor  spar  occurs  mostly  in  crystals  of  various  forms,  the 
principal  of  which  is  the  octahedron  with  its  varieties,  the 
cube  and  the  rhomboidal  dodecahedron ;  also,  massive  and 
in  specks ;  it  has  an  uneven  or  splintery  fracture ;  is  trans- 
parent or  translucent  on  the  edges ;  possesses  simple  refrac- 
tion of  light ;  a  vitreous  lustre ;  its  colors  are  green,  yellow, 
gray,  blue,  and  white ;  also  purple  and  red,  in  all  their 
various  shades,  from  the  violet  to  the  rose-red. 

It  scratches  lime,  but  not  glass ;  yields  to  the  knife ;  has 
a  white  streak-powder;  its  specific  gravity  is  3*14  to  3'17; 
it  becomes  electric  by  rubbing  ;*  before  the  blowpipe  it 
fuses  with  ebullition  into  an  opaque  globule,  but  with 
borax,  into  a  transparent  glass ;  when  pulverized  and  treat- 
ed with  heated  sulphuric  acid,  it  emits  fluoric  acid  gas, 
which  is  employed  in  etching  on  glass ;  phosphoresces  when 
thrown  on  hot  iron ;  it  consists  of  fluoric  acid  and  lime. 


834          A  POPULAR  TREATISE  ON  GEMS. 

From  the  variety  and  beauty  of  its  colors,  it  is  known,  when 
cut,  in  trade,  under  the  various  names  of  false  emerald, 
false  amethyst,  false  ruby,  and  false  topaz,  according  to  the 
color  it  exhibits.  It  is  mostly  found  in  metalliferous  veins, 
and  very  rarely  in  the  newer  formations.  Its  localities  are 
in  Baden,  Bohemia,  Saxony,  St.  Gothard,  at  Derbyshire 
and  Devonshire,  in  England,  and  the  United  States,  in  the 
last  of  which  countries  it  occurs  of  most  beautiful  colors  in 
fine  crystals ;  from  a  lately-discovered  locality  at  Rnssy,  in 
St.  Lawrence  county,  State  of  New  York,  I  have  specimens 
of  crystals  two  feet  long  and  five  wide.  It  is  found  in  Illi- 
nois, seventeen  miles  from  Shawneetown ;  Blue  Ridge, 
Maryland ;  Smith  county,  Tennessee ;  at  Franklin  Furnace, 
and  Hamburgh,  New  Jersey;  Saratoga  Springs,  and  at 
Alexandria,  New  York;  Middletown  and  Huntingdon, 
Connecticut ;  Thetford  and  Southampton  lead  mines,  Mas- 
sachusetts, and  on  the  White  Mountains,  New  Hampshire. 
Fluor  spar  is  cut  for  ring-stones  and  shirt-buttons,  and 
particularly  in  such  forms  as  are  intended  to  be  substituted 
for  other  gems ;  in  Derbyshire  there  have  been  large  mills 
for  grinding,  cutting,  and  polishing  the  flour  spar  into  vases, 
cups,  obelisks,  plates,  candlesticks,  &c.,  ever  since  1765, 
and  there  are  now  more  manufactories,  principally  at 
Derby.  That  fluor  spar  which  may  be  called  the  nodular 
variety,  and  the  colors  of  which  run  in  bands  or  zones,  is 
only  found  in  a  single  mine  near  Castleton,  Derbyshire,  and 
is  known  by  the  technical  name  of  Derbyshire-spar  or  Blue 
John ;  it  is  used  for  various  ornaments,  to  be  met  with  all 
over  the  world,  in  parlors  or  mineral  collections.  In  order 
to  heighten  the  various  colors  in  the  ornamental  specimens, 
before  they  are  polished,  they  are  heated  to  a  certain  de- 
gree, when  the  dark  spots,  or  tints,  disappear,  and  the 
colored  bands  become  more  distinct,  and  assume  a  peculiar 
purple  or  amethystic  hue. 


MALACHITE.  335 

Fluor  spar  is  often  intermixed  with  lead  ore,  called  galena, 
which  produces,  when  polished,  a  beautiful  appearance. 
Ornaments  of  fluor  spar  still  command  a  high  price,  which, 
however,  depends  a  good  deal  on  the  perfect  qualities  of 
the  various  specimens,  their  color,  gize,  &c. 

A  translucent  variety  of  fluor  spar,  called  chlorophane 
(found  in  Cornwall,  England,  in  Siberia,  and  principally  in 
the  United  States,  at  New  Stratford,  Connecticut),  is  of 
beautifully  variegated  colors,  but  principally  blue,  violet,  and 
green ;  it  is  chiefly  interesting  on  account  of  its  phospho- 
rescence ;  when  put  on  hot  iron  in  a  dark  room,  it  emits  a 
most  beautiful  emerald-green  light.  One  of  the  first  locali- 
ties of  chlorophane  discovered  in  this  country,  was  at  Shee- 
konk,  Massachusetts,  near  the  summer  residence  of  the 
Hon.  Tristam  Burges,  about  one  and  a  half  miles  from* 
Providence.  It  is  massive,  opaque,  and  of  a  deep  purple 
color.  It  phosphoresces  readily  on  being  projected  upon  a 
moderately-heated  shovel,  when  it  loses  its  color  and  be- 
comes white.  It  also  occurs  of  a  crystalline  structure  in 
Wrentham,  Massachusetts,  near  the  Cumberland  and  Rhode 
Island  line,  in  the  vicinity  of  Diamond  Hill.  A  beautiful 
vase  of  Derbyshire-spar,  as  also  crystalline  groups,  may 
be  seen  in  the  collection  of  the  New  York  Lyceum  of 
Natural  History. 

MALACHJTE. 

The  name  of  this  mineral  is  from  the  Greek,  alluding  to 
its  color ;  it  was  well  known  to  the  ancients ;  Theophras- 
tus  called  it  the  pseudo-emerald ;  it  was  worn  by  many  as 
an  amulet. 

It  occurs  tuberose,  globular,  reniform,  mainmillary,  an<J 
stalactiform ;  also,  in  fibres ;  it  has  an  uneven,  conchoidal, 
and  splintery  fracture ;  it  is  opaque ;  of  a  dull  and  shining 


336  A  POPULAR  TREATISE  ON  GEMS. 

lustre ;  and  has  an  emerald  or  verdigris  green  color,  alter- 
nating sometimes  in  stripes  of  different  shades  of  green. 
It  scratches  lime,  but  not  glass ;  its  streak-powder  is  of 
lighter  color  than  the  mineral;  its  specific  gravity  is  3*67  ; 
before  the  blowpipe,  it  decrepitates  and  turns  black ;  with 
borax,  it  is  reduced  to  a*  metallic  grain ;  it  effervesces  with 
nitric  acid ;  is  dissolved,  and  forms  a  blue  color  with  am- 
monia ;  it  consists  of  oxide  of  copper,  carbonic  acid,  and 
water. 

Malachite  is  found  in  various  rocks,  primitive  as  well 
as  secondary,  in  gangues  and  strata.  The  finest  specimens 
are  obtained  in  Siberia,  Tyrol,  France,  Hungary,  Norway, 
Sweden,  England,  Bohemia,  and  the  United  States,  at  a 
great  number  of  localities,  but  either  in  small  specimens, 
*or  as  a  coating  of  other  copper  ores,  which  will  ever  ren- 
der jt  useless  for  ornamental  purposes.  The  principal  locali- 
ties in  this  country  are  in  New  Jersey,  Maryland,  Connecti- 
cut, and  at  the  various  copper-mines ;  it  is  also  found  in  the 
island  of  Cuba,  from  which  place  I  have  seen  some  good 
compact  specimens. 

Some  very  fine  specimens  of  compact  malachite  from 
Siberia,  were  presented  to  the  New  York  Lyceum  of 
Natural  History,  by'  Charles  Cramer,  Esq.,  of  St.  Peters- 
burg. I  have  also  seen  some  excellent  specimens  of  mala- 
chite in  the  collection  of  Dr.  Martin  Gay,  at  Boston ;  Dr. 
Chilton,  of  New  York,  &c. 

Malachite,  when  cut,  takes  a  high  polish,  which  well 
adapts  it  for  various  ornaments,  such  as  rings,  pins,  ear- 
rings, &c.  Snuff-boxes,  candlesticks,  mosaics,  &c.,  are  like- 
wise made  from  it.  In  general,  the  specimens  are  assorted, 
and  the  best  pieces  cut  on  a  leaden  wheel  with  emery,  and 
polished  with  rotten-stone  on  a  tin  plate.  Very  large  spe« 
cirnens  are  used  for  table  plates  and  vases. 

The  value  of  the  malachite  is  not  high,  being  very  abun- 


MALACHITE.  337 

dant ;  yet  much  depends  upon  the  size  of  the  various  spe- 
cimens. At  St.  Petersburg,  a  very  large  slab,  said  to  be 
in  the  collection  formerly  belonging  to  Dr.  Guthrie,  thirty- 
two  inches  long,  seventeen  inches  broad,  and  two  inches 
thick,  was  valued  at  twenty  thousand  francs.  Many  rooms 
in  several  European  palaces  are  laid  out  with  malachite ; 
and  the  Mineralogical  Museum,  at  Jena,  possesses  a  large 
collection  of  malachite,  which  was  presented  by  the  Grand 
Duchess  of  Saxe  Weimar,  a  Russian  princess. 

An  apartment  in  the  Grand  Trianon,  at  Versailles,  is 
furnished  with  pier  and  centre  tables,  mantel-pieces,  ewers 
and  basins,  and  enormous  ornamental  vases  of  malachite, 
the  gift  of  the  Emperor  Alexander  to  Xapoleon. 

The  malachite  furniture  exhibited  by  the  Russian  govern- 
ment at  the  London  Exhibition,  excited  so  much  admira- 
tion and  was  sold  at  such  high  prices,  that  the  author  con- 
siders himself  justified  in  copying  a  part  of  the  report  by 
the  jury  on  inlaid  work  in  malachite : 

"  Malachite  is  a  peculiar  mammilla  ted  or  stalagmitic  form 
of  the  green  carbonate  of  copper,  chiefly  found  in  an  avail- 
able state  for  inlaid  work,  in  a  very  few  localities  in 
Siberia,  and  lately  in  South  Australia.  It  has  long  been 
employed  in  Russia  in  this  manufacture.  The  mineral  is 
remarkable  for  its  fine  emerald-green  color  (often  present- 
ing several  distinct  shades  in  the  same  specimen),  its  bril- 
liant and  silky  lustre,  and  compact  texture.  It  is  softer 
than  marble,  very  much  heavier,  and  by  no  means  so  easily 
worked,  owing  to  its  brittleness  and  the  concentric  arrange- 
ment it  generally  presents.  It  can  rarely  be  found  in 
masses  weighing  more  than  ten  to  twenty  pounds,  and 
good  specimens  have  a  very  high  value,  as  the  finer  kinds 
are  used  exclusively  for  decorative  purposes. 

"  The  most  important  locality  at  present  known  for  the 
finer  kinds  of  Siberian  malachite,  is  in  the  copper  ground 


338  A  POPULAR  TREATISE  ON  GEMS. 

of  Nijug  Tagilsk,  in  the  government  of  Ekaterinenburg,  on 
the  river  Tura,  a  tributary  of  the  Irtish,  on  the  Siberian  side 
of  the  Uralian  mountains,  in  latitude  57  J°  N.,  longitude  56° 
E.  In  a  mine  at  this  place,  belonging  to  Messrs.  Demidoff, 
Sir  Roderick  Murchison  has  described  an  immense  mass  of 
malachite,  which  at  the  time  of  his  visit,  a  few  years  back, 
had  been  recently  discovered  at  the  depth  of  two  hundred 
and  eighty  feet,  strings  of  green  copper  conducting  to  it ; 
and  these  strings  increasing  in  width  and  value,  were  found 
to  terminate  in  a  vast  irregular  botryoidal  mass,  estimated 
to  contain  not  less  than  half  a  million  of  pounds  of  this 
valuable  mineral.  The  larger  blocks,  when  exposed  to  the 
air,  break  up  into  smaller  fragments,  rarely  weighing  more 
than  from  one  to  four  pounds. 

"  It  is  by  no  means  a  modern  application  of  this  material, 
to  employ  it  in  inlaying  or  veneering  for  decorative  pur- 
poses; and  few  palaces  or  large  public  museums  in  the 
principal  capitals  of  Europe,  are  without  specimens,  mark- 
ing the  progress  of  its  manufacture  from  time  to  time,  and 
generally  regarded,  from  their  great  rarity,  cost,  and  beauty, 
as  worthy  of  being  made  imperial  and  royal  presents.  It 
is,  however,  only  lately  that  Messrs.  Demidoff,  the  owners 
of  the  mine  in  which  the  mineral  occurs,  have  established 
in  St.  Petersburg  a  manufactory,  where,  after  numerous 
trials  and  the  expenditure  of  much  capital,  labor,  and  in- 
genuity, it  has  been  found  possible  to  produce  such  works 
as  those  sent  to  the  London  Exhibition,  and  in  testimony 
of  the  magnitude  and  importance  of  the  objects  exhibited, 
their  extraordinary  beauty  and  richness,  the  excellence  of 
the  production,  and  the  application  of  the  various  new 
methods  of  manufacture,  Messrs.  Demidoff  have  been 
awarded  the  highest  premiums.  These  are  chiefly  seen  in 
the  construction  of  the  doors,  and  more  especially  in  the 
ingenious  and  beautiful  manner  in  which  the  pattern  is 


MALACHITE.  339 

adapted  to  the  material,  the  detached  pieces  of  mineral 
being  fitted  to  each  other  so  as  to  preserve  the  pattern ; 
they  may  also  be  noticed  in  the  nature  of  the  cement, 
which  being  mixed  with  broken  fragments  of  the  malachite 
itself  does  not  interfere  with  the  plan,  or  in  any  way  injure 
the  effect  of  the  whole. 

"  The  working  of  malachite  on  a  large  scale  is  extremely 
tedious  and  laborious,  and  the  mode  of  operation  is  too 
long  to  detail  in  this  treatise. 

"  The  quantity  of  malachite  obtained  from  the  mine  and 
brought  into  market  annually  is  very  small,  and  the  price 
of  the  raw  material  is  considerable,  it  ranges  from  twelve 
to  seventeen  shillings  sterling  per  pound,  according  to  color 
rather  than  veining,  the  darker  colors  being  cheapest; 
there  are  four  shades  quoted,  denominated  respectively, 
foncee,  ordinaire,  claire,  and  pale  ;  but  these  are  also  sub- 
divided, the  two  first  into  ronde  and  longv.e,  the  others 
into  ronde,  longue,  and  tachetee.  A  large  proportion  of 
the  malachite  in  the  specimens  exhibited  was  of  very  good 
color,  and  the  average  value  probably  exceeded  fifteen 
shillings  sterling  per  pound. 

"The  objects  exhibited  consisted  of  a  pair  of  fold- 
ing-doors, several  vases,  a  chimney-piece,  a  table,  a  set  of 
chairs,  and  sundry  smaller  articles;  of  these,  the  doors  and 
vases  were  at  once  the  most  important  and  the  most  highly 
finished,  and  it  is  understood  that  the  former  required  the 
constant  labor  of  thirty  workmen  employed  by  day  and 
night  during  a  whole  year.  They  were  most  skilfully  and 
and  beautifully  planned,  and  the  workmanship  was  in  all 
respects  admirable." 

There  are  fluted  Corinthian  columns  of  malachite  in 
some  churches  in  St.  Petersburg,  and  many  other  large 
ornaments  of  large  slabs  of  malachite  in  the  palace  of  the 
King  of  Prussia,  at  Potsdam. 


340          A  POPULAR  TREATISE  ON  GEMS. 

A  large  oblong  table,  inlaid  with  malachite,  partly  Rus- 
sian and  partly  Australian,  was  also  exhibited  by  a  manu- 
facturer of  Paris,  with  specimens  of  azurite  (blue  carbonate 
of  copper),  but  were  all  put  in  the  shade  by  the  Russian 
articles. 

SATIN    SPAR. 

This  mineral  occurs  stalactiform,  globular,  reniform,  and 
massive ;  it  is  of  a  fibrous  texture  (that  is,  of  fine  delicate 
fibres  closely  adhering  together),  a  pearly  lustre,  and  is 
translucent  on  the  edges ;  the  colors  are  snow-white,  yel- 
lowish-white, or  pale-red,  colored  by  metallic  oxides.  It 
scratches  gypsum,  but  not  glass ;  specific  gravity,  2*70 ;  be- 
comes electric  by  rubbing ;  before  the  blowpipe  is  infusible, 
and  changes  into  quicklime,  but  borax  reduces  it  to  a  clear 
glass.  It  effervesces  and  dissolves  with  nitric  acid;  and 
consists  of  lime  and  carbonic  acid.  Satin  spar  is  called  by 
mineralogists  fibrous  limestone,  and  is  found  in  the  coal 
formations,  and  in  the  cavities  of  several  limestones.  The 
finest  specimens  are  found  in  Cumberland  and  Derbyshire, 
England ;  in  Hungary ;  and  in  the  United  States,  near 
Baltimore,  in  Pennsylvania,  also  at  Westfield  and  Newbury- 
port,  Massachusetts,  where  splendid  specimens  five  inches 
long  are  obtained,  according  to  Professor  Hitchcock.  It 
takes  a  fine  polish,  and  is  distinguished  by  its  extraordinary 
fine  satin  lustre,  and  is  therefore  used  for  various  articles  of 
jewelry,  such  as  ear-rings,  necklaces,  beads,  and  also  for 
inlaid  work ;  large  specimens  are  used  for  snuff-boxes. 

Satin-spar  beads  have  been  in  great  favor  as  necklaces 
and  ear-rings,  and  were  sold  a  few  years  ago  in  England  at 
very  high  prices.  In  modern  times,  the  satin  beads  or 
pearls  have  been  imitated  to  a  great  extent  in  France  and 
Germany,  in  white  and  deep-yellow  colors :  glass  beads,  of 
a  bluish-white  tinge,  and  hollow,  are  made  to  imitate  the 


ALABASTER.  341 

reflection  of  the  satin  spar,  by  means  of  the  scales  of  a 
small  river-fish  called  the  bleak,  that  are  suspended  in  dis- 
solved isinglass,  and  dropped  into  the  bulbs,  which  are  then 
turned  in  all  directions  in  order  to  spread  the  solution 
equally  over  their  interior  surface ;  in  this  way  the  glass 
bulbs  assume  the  natural  color  and  brilliancy  of  satin  spar ; 
they  are  harder,  however,  and  it  is  easy  to  detect  them  on 
that  account. 

Fine  specimens  may  be  seen  at  the  New  York  Lyceum 
of  Natural  History,  also  in  the  collection  of  Dr.  Gay,  of 
Boston. 

Satin  gypsum,  which  bears  the  greatest  resemblance  to 
satin  spar,  and  only  differs  in  its  chemical  constituents  (hav- 
ing sulphuric  acid,  instead  of  carbonic,  as  a  component  part), 
is  much  used  for  the  same  kind  of  ornamental  purposes,  and 
is  more  abundant  over  the  world.  I  have  seen  very  splen- 
did specimens  at  South  Boston,  in  the  beautiful  collection 
of  minerals  belonging  to  Francis  Alger,  Esq.,  who  brought 
them  from  Nova  Scotia,  and  who  (as  also  Dr.  C.  T.  Jack- 
sou)  has  given  so  valuable  a  description  of  all  the  mineral 
treasures  of  that  province. 

Satin  gypsum  is,  however,  much  softer  than  satin  spar, 
and  is  much  easier  scratched ;  for  which  reason  it  is  not 
so  generally  employed. 

ALABASTER. 

This  mineral  is  a  compact  gypsum,  and  occurs  massive, 
with  a  compact  fracture ;  it  is  translucent ;  has  a  glim- 
mering lustre,  and  its  colors  are  white,  reddish,  or  yel- 
lowish. 

The  purest  kinds  of  this  mineral  are  used  in  Italy  for 
vases,  cups,  candlesticks,  and  other  ornaments.  It  is  found 
at  Castelino,  in  Tuscany,  thirty-five  miles  from  Leghorn, 
at  two  hundred  feet  below  the  surface  of  the  earth. 


342  A   POPULAR   TREATISE   ON   GEMS. 

The  yellow  variety,  called  by  the  Italians,  alabastro  ago* 
tato,  is  found  at  Sienna ;  another  variety  of  a  bluish  color, 
obtained  at  Guercieto,  is  remarkably  beautiful,  being 
marked  with  variegated  shades  of  purple,  blue,  and  red. 
The  above  alabasters  are  carbonates  of  lime. 

The  principal  manufactory  of  alabaster  ornaments  is  at 
Valterra,  thirty-six  miles  from  Leghorn,  where  about  five 
thousand  persons  live  by  this  kind  of  labor.  In  making, 
they  require  great  care,  and  must  be  preserved  from  dust, 
as  the  alabaster  is  difficult  to  clean.  Talcum,  commonly 
called  French  chalk,  will  remove  dirt,  but  the  best  mode 
of  restoring  the  color,  is  to  bleach  the  alabaster  on  a  grass- 
plat.  Gum  water  is  the  only  cement  for  uniting  broken 
parts. 

Plaster  of  Paris  is  likewise,  a  compact  gypsum,  but 
contains  a  small  portion  of  carbonic  acid,  which  makes  it 
effervesce  when  treated  with  acids.  It  was  formerly  ex- 
ported only  from  Montmartre,  near  Paris,  hence  its  name ; 
it  is  much  used  in  ornamenting  rooms  in  stucco,  in  taking 
impressions  of  medals,  in  casting  statues,  busts,  vases, 
time-piece  stands,  candelabras,  obelisks,  and  for  many  other 
purposes. 

The  common  plaster  of  Paris  is  ground  after  being  cal- 
cined ;  and  in  this  condition  it  has  the  property  of  forming 
a  pliable  mass  with  water,  which  soon  hardens,  and  assumes 
the  consistency  of  stone. 

Oriental  alabaster  is  not  a  sulphate  but  a  true  carbonate 
of  lime,  and  on  account  of  its  peculiar  tint  and  trans- 
parency, and  as  it  appears  that  it  was  formed  similar  to 
stalagmite,  it  was  called  by  the  ancients,  alabaster;  the 
large  vase  of  this  Oriental  alabaster  which  was  so  justly 
and  so  much  admired  by  the  thousands  of  spectators  at  the 
London  Exhibition,  was  executed  by  Dallamada,  of  Rome. 
It  was  really  a  magnificent  piece  of  workmanship,  being 


AMBEE.  348 

from  a  large  block  and  the  whole  work  of  one  entire  piece, 
the  vase,  the  handles,  which  consisted  of  serpents,  along 
with  the  tazza  and  the  extremely  fine  polish,  displayed  the 
great  ingenuity  of  the  master. 

A  hollow  altar  of  Oriental  alabaster,  provided  with  a 
lamp  and  intended  to  show  the  remarkable  transparency 
of  the  material,  and  of  excellent  workmanship,  along  with 
a  great  many  statues  and  groups  of  life-size  figures,  were 
exhibited  both  in  the  London  and  New  York  Exhibi- 
tions. 

A3IBER. 

This  gem  was  known  to  the  inhabitants  of  remote  ages ; 
the  Phoenicians  sailed  to  the  Baltic  (the  Glessany  islands), 
for  the  sole  purpose  of  obtaining  amber,  which  they 
wrought  into  chains  and  other  ornaments,  that  were  sold 
to  the  Greeks,  who  called  the  same  electron.  In  the  Trojan 
war,  as  Homer  reports,  the  women  wore  necklaces  of 
amber.  Its  electric  properties  were  likewise  known,  for 
Thales  was  so  much  surprised  at  that  phenomenon,  that  he 
attributed  it  to  a  soul  in  the  amber ;  and  Pliny  says  that 
amber  is  revived  by  heat,  the  nature  of  electricity  not 
being  understood.  It  was  also  worn  as  an  amulet,  and 
used  for  medicine.  The  ancients  could  not  agree  as  to  its 
origin :  Philemon,  according  to  Pliny,  classed  it  as  a  fossil ; 
Tacitus,  however,  judging  from  the  insects  held  in  it,  con- 
cluded it  must  be  a  vegetable  juice,  whence  its  name  in 
Latin,  succinum,  or  juice.  Many  naturalists  have,  until 
lately,  considered  amber  as  a  mineral;  but  it  has  been 
satifactorily  proved  by  Schweigger  and  Brewster,  from  its 
chemical  characters,  and  polarizing  light,  to  be  a  gum-resin, 
and  that  it  is  the  juice  of  a  tree,  called  the  amber-tree,  now 
extinct. 

Amber  occurs  in  nodules  or  roundish  masses,  from  the 


344  A  POPULAR  TREATISE  ON  GEMS. 

size  of  grains  to  that  of  a  man's  head ;  and  sometimes  in 
specks;  it  has  a  conchoidal  fracture;  is  transparent  and 
translucent ;  possesses  single  refraction  of  light ;  a  resin- 
ous lustre  in  a  high  degree :  its  colors  are  wine  and  wax 
yellow,  greenish  or  yellowish  white,  or  reddish-brown ; 
sometimes  the  colors  vary  in  layers.  It  scratches  gypsum, 
but  is  attacked  by  carbonate  of  lime ;  its  streak-powder  is 
yello wish- white ;  it  has  a  specific  gravity  of  1*08  to  1*10; 
it  becomes  electric  by  rubbing.  Before  the  blowpipe  it 
burns  with  a  yellowish  and  bluish  green  flame,  emitting  at 
the  same  time  a  dense  and  agreeable  smoke,  and  leaving  a 
carbonaceous  residuum;  heated  oil  softens  and  makes  it 
pliable ;  it  does  not  melt  as  easily  as  other  resins,  requiring 
51 7°  Farenheit ;  it  yields  by  dry  distillation  an  acid  which 
is  called  succinic  acid,  also  an  essential  oil,  known  by  the 
name  of  oil  of  amber,  and  in  the  retort  remains  a  brown 
mass,  called  the  resin  of  amber,  which  is  used  in  the  arts 
as  amber  varnish  ;  any  essential  oil,  or  spirits  of  turpentine 
may  be  used  for  procuring  the  resin ;  fat  oils  dissolve 
amber  perfectly;  its  elementary  constituents  are  carbon, 
hydrogen,  and  oxygen,  with  some  lime,  alumina,  and 
silex. 

Amber  is  found  either  thrown  up  by  the  sea,  or  in  the 
small  rivers  near  it ;  sometimes  in  alluvial  deposits  of  sand 
or  gravel  in  the  vicinity  of  the  sea,  or  in  bituminous  forma- 
tions, such  as  lignite,  bituminous  wood,  or  jet,  where  crys- 
tallized minerals  are  at  the  same  time  found,  such  as  iron 
pyrites,  &c. 

Its  geological  distribution  is  in  the  green-sand  formation, 
or,  according  to  De  la  Beche,  the  stratified  rocks,  between 
the  third  and  fourth  large  group. 

Amber  occurs  in  the  greatest  abundance  on  the  Prussian 
coast,  in  a  bed  of  bituminous  coal,  where  it  is  washed  out 
or  cast  ashore  during  the  autumnal  storms  on  the  coast  of 


AMBER.  345 

Pomerania  and  Prussia  proper,  between  Konigsberg  and 
Dantzic ;  it  is  also  obtained  there  by  sinking  a  shaft  into 
the  coal,  and  is  mined  in  a  systematic  way.  All  along  the 
line  of  the  Baltic  coast,  at  Corn-land,  Livonia,  Pomerania, 
and  in  Denmark,  it  is  picked  up.  On  the  Sicilian  coast, 
near  Catania,  sometimes  very  peculiarly  tinged  blue,  it  is 
also  found.  In  Greenland,  at  Hasen  island,  it  occurs  in 
brown  coal.  Near  Paris  it  occurs  in  clay.  It  is  also  found  in 
China.  One  of  the  largest  specimens  ever  met  with  on  the 
Baltic  was  found  in  1811,  measuring  fourteen  inches  in 
length  by  nine  inches  in  breadth,  and  weighing  twenty-one 
pounds. 

I  had  in  my  own  coUection,  in  the  year  1831,  a  splendid 
wax-yellow  amber,  from  the  Baltic,  which  measured  about 
sixty  cubic  inches,  and  weighed  nearly  two  pounds.  It  is 
also  found  on  the  Danish  coast,  and  in  Greenland,  Sicily, 
Monrovia,  Poland,  France,  and  the  West  Indies.  A  sailor 
is  said  to  have  found  a  remarkable  specimen,  eighteen 
inches  in  length,  in  a  singular  manner ;  the  discoverer  acci- 
dentally seated  himself  on  it,  when  he  became  so  attracted 
to  the  amber,  excited  by  his  natural  heat,  that  it  was  with 
some  difficulty  he  could  detach  himself  from  it. 

In  the  United  States  we  find  amber  at  Cape  Sable,  in 
Maryland,  in  a  bed  of  lignite,  in  masses  of  four  and  five 
inches  diameter ;  also,  near  Trenton,  and  at  Camden,  New 
Jersey,  where  a  transparent  specimen,  several  inches  in 
diameter,  was  found.  According  to  Professor  Hitchcock, 
it  is  found  at  Martha's  Vineyard,  Gayhead,  and  at  Nan- 
tucket.  At  the  latter  place,  a  light-colored  specimen  was 
found,  of  three  or  four  inches  diameter,  which  is  in  the 
collection  of  T.  A.  Green,  Esq.,  of  New  Bedford. 

The  production  of  amber  depends  upon  the  position  of 
the  respective  localities ;  whether  it  is  found  among  sand 
and  gravel,  in  mines  called  amber  mines,  or  in  the  sea,  on 


346  A   POPULAR   TREATISE    ON   GEMS. 

the  shore,  or  in  smaller  rivers  near  the  sea-coast ;  and  the 
modes  of  collecting  are  threefold : 

1.  The  amber  mines,  which  are  numerous  in  Prussia,  are 
wrought  like  other  mines,  and  explored  to  a  depth  of  more 
than  one  hundred  feet.     Shafts  are  constructed  for  raising 
the  product  from  the  interior  of  the  mines ;  the  miners  dig 
until  they  reach  the  amber  vein,  which  is  generally  found 
after  passing  a  stratum  of  sand  and  a  bed  of  clay  of  twenty 
feet  thickness,  and  another  stratum  of  decomposing  trees  or 
lignite,  which  may  be  fifty  feet  through ;  they  come  then  to 
the  pits,  which  the  characteristic  color  of  the  soil  is  the  best 
indication  to  search  for. 

2.  The  second  mode  of  collecting  amber  is  practised, 
generally  after  a  storm,  by  the  fishermen,  who  either  wade 
into   the  water,   provided  with  leather  dresses,  to   their 
necks,  or  use  small  boats,  and  find  at  the  depth  of  three 
fathoms  the  floating  amber. 

3.  It  is  mostly,  however,  collected  in  large  quantities  on 
the  shore,  after  having  been  thrown  up  by  severe  storms. 

The  amber  fishermen  are,  by  practice,  pretty  well  skilled 
in  finding  out  the  spots  where  the  largest  quantities  may 
be  obtained. 

Amber  from  the  mines  does  not  essentially  differ  from 
that  of  the  sea,  excepting  that  the  former  is  rather  more 
brittle,  and  is  often  covered  with  an  earthy  crust. 

The  amber  is  assorted  before  it  comes  into  the  hands  of 
the  lapidary  or  merchant,  and  according  to  size  and  clear- 
ness of  color,  it  receives  different  technical  names.  Thus, 
there  are — 

1.  The  exquisite  specimens,  which  are  perfectly  pure, 
transparent,  and  compact,  weighing  from  five  to  six  ounces 
or  more ;  these  are  employed  in  larger  ornaments  and  spe- 
cimens of  the  arts,  and  bring  the  highest  price. 

2.  The  ton  stones,  which  weigh  from  a  quarter  of  an 


AMBER.  347 

ounce  to  four  ounces;  the  largest  or  purest  pieces  of  which 
are  used  for  jewelry,  and  the  impure  for  incense  or  med- 
icine. 

3.  The  nodules  are  still  smaller. 

4.  The  varnish  stones  are  still  smaller  than  the  former, 
but  are  very  pure  and  hard,  so  as  to  be  easily  pulverized, 
and  are  used  for  varnishes,  sealing-wax,  &c. 

5.  The  sandstones  are  very  small,  opaque,  and  perforated 
pieces. 

6.  The  lumps  are  large  but  impure  specimens,  unfit  for  a 
lapidary's  use ;  they  are  sold  as  specimens,  or  employed  as 
incense,  or  for  the  manufacture  of  succinic  acid. 

7.  Refuse  are  those  pieces  which  fall  off  at  the  lapidary's 
bench. 

The  pure  amber  receives  from  the  lapidary  distinct 
names,  according  to  the  shades  of  color  it  possesses,  such  as 
egg,  pale,  and  light  yellow,  and  so  into  its  brownish  shades. 
The  assorted  amber  is  treated  according  to  the  various 
purposes  it  is  intended  for,  and  receives  its  requisite  form 
by  cleaving  with  an  appropriate  instrument,  by  which,  also, 
the  external  crust  is  removed.  It  is  generally  believed  that 
the  worse  the  crust  is  in  appearance,  the  more  beautiful  is 
the  interior  of  the  amber. 

Amber,  taking  a  very  high  polish,  is  employed  for  a 
great  many  purposes  of  jewelry,  and  for  various  ornaments, 
such  as  beads,  necklaces,  bracelets,  ear-rings,  buttons,  rosa- 
ries, mouth-pieces  for  pipes,  cane-beads,  snuffboxes,  work- 
boxes,  &c.  It  is  generally  wrought  on  the  turner's  lathe, 
by  steel  instruments,  and  is  easily  bored  ;  it  is  polished  on 
a  leaden  wheel,  with  pumice-stone,  then  with  linen  or  a  hat- 
body  and  rotten-stone,  and  lastly  by  rubbing  it  with  the 
hand.  Common  specimens  are  polished  with  a  linen  rag, 
chalk,  and  water.  Beads  of  amber  must  be  drilled  before 
receiving  the  facets.  In  cutting  and  working  amber,  care 


348  A  POPULAR  TREATISE  ON  GEMS. 

must  be  taken  not  to  overheat  it  by  friction,  as  it  will  then 
be  liable  to  crack.  Amber  has  occasionally  been  cut  into 
cameos,  busts,  images,  <fcc. 

Impure  amber  pieces  may  be  much  improved  by  wrap- 
ping them  in  paper  and  allowing  them  to  digest  for  forty 
hours  in  hot  ashes,  in  a  pot  filled  with  sand ;  or  by  boiling 
them  with  gradually  increased  heat  in  linseed  oil.  Amber 
may  also  be  colored  red,  blue,  and  violet,  and  dissolved  in 
absolute  alcohol ;  it  may  be  cast  into  different  ornaments. 
Broken  amber  may  be  mended  by  a  cement  of  linseed  oil, 
gum  mastic,  and  litharge ;  or  by  moistening  the  ends  of 
both  pieces  with  potash,  warming  the  same,  and  pressing 
the  parts  together. 

The  price  of  amber  was,  in  former  times,  much  higher 
than  at  present,  but  size,  color,  and  transparency  always 
govern  the  same.  A  pure  exquisite  specimen  of  one  pound 
is  sold  for  forty  dollars ;  but  most  good  specimens  are  sent 
to  Armenia,  the  East,  and  Turkey,  to  which  places  manufac- 
tured amber  goods  to  the  amount  of  fifty  to  sixty  thousand 
dollars  are  annually  exported  from  one  manufactory  at 
Stolpe,  in  East  Prussia. 

Amber  is  often  adulterated  in  various  ways,  and  more 
especially  with  gum  copal,  which  is  palmed  upon  the  igno- 
rant for  amber,  and  which  does  actually  resemble  it  in 
many  respects :  for  both  are  of  the  same  color ;  both  be- 
come negatively"  electric  by  friction ;  both  have  nearly  the 
same  specific  gravity;  and  both  give  a  pleasant  odor  in 
burning ;  hence  when  wrought  as  jewelry  or  ornaments,  it 
is  not  easy  to  distinguish  the  one  from  the  other.  One 
mode  of  detection  was  pointed  out  by  the  Abbe  Hatty : 
"  If,"  says  he,  "  a  fragment  of  amber  be  attached  to  the 
point  of  a  knife  and  inflamed,  it  will  burn  with  some  noise 
and  a  kind  of  ebullition,  but  without  liquifying  so  as  to 
flow,  and  if  it  should  fall  on  any  flat  surface  it  rebounds  a 


AMBER.  349 

little;  whereas  copal,  under  similar  circumstances,  melts 
and  falls  in  drops,  which  become  flattened."  My  own  ex- 
perience has  taught  me  the  following  distinguishing  charac- 
teristics :  first,  the  electrometer,  a  small  instrument  com- 
posed of  a  brass  needle,  suspended  on  a  pin,  is  the  most  esse^ 
tial  distinguishing  guide, — for  amber,  on  being  rubbed, 
will  excite  the  instrument  about  ten  degrees  more  than 
copal ;  secondly,  amber,  on  being  brought  before  the  fire, 
requires  a  moderately  high  temperature  for  melting  it,  and 
exhibits  no  kind  of  ebullition,  whereas  copal  easily  liqui- 
fies, burns  with  much  smoke,  and  decrepitates  more  than 
amber. 

Amber  is  likewise  adulterated  by  gum  arabic,  gum  thus, 
shellac,  and  glass  pastes.  The  last  can  easily  be  distin- 
guished by  their  hardness,  and  the  others  by  their  solubility 
in  hot  water. 

Amber  very  frequently  has  inclosed  within  it  insects, 
such  as  flies,  beetles,  &c.,  in  a  state  of  complete  preserva- 
tion. Such  specimens  are  much  sought  for,  and  command 
a  very  high  piice ;  and  on  that  account  the  adulterations 
are  mostly  practised,  and  in  the  following  manner :  either 
by  boring  a  hole  in  the  amber,  introducing  the  beetle, 
filling  it  up  with  pulverized  gum-mastic,  and  then  let- 
ting it  melt  over  a  charcoal  fire  ;*or  by  melting  the  amber, 
throwing  in  the  insects,  and  letting  it  cool.  The  former 
adulteration  may  easily  be  detected,  since  the  mastic  will 
never  be  able  to  combine  closely  with  the  amber,  and  shows 
more  or  less  cracks  and  fissures ;  but  the  latter  is  scarcely 
to  be  detected,  without  a  scientific  investigation  of  the  in- 
closed insects,  which  in  the  natural  specimens  do  not  exist 
in  the  present  world,  being  called  antediluvian,  or  extinct 
species  of  animals. 

The  most  extensive  use  of  this  elegant  material  is  for  the 
manufacture  of  the  mouth-piece,  an  essential  constituent  ol 


350  A   POPULAR   TREATISE    ON   GEMS. 

the  genuine  Meerschaum  and  Turkish  pipe.  Amber  mouth 
pieces  have  always  been  in  great  request  in  the  East,  where 
they  command  great  prices ;  but  in  the  United  States  a  fash- 
ionable taste,  similar  to  other  countries,  has  sprung  up  of 
late,  which  bids  fair  to  outvie  the  East.  No  young  man  of 
any  pretensions  to  smoking  cigars,  can  do  so  without  his 
meerschaum  and  amber  cigar-holder.  The  dearer  he  pays 
for  this  luxury,  the  more  respected  he  considers  himself. 
There  is  a  current  belief  in  Turkey,  that  amber  is  incapa- 
ble of  transmitting  infection,  and  as  it  is  a  great  mark  of 
politeness  to  offer  the  pipe  to  a  stranger,  this  supposed 
negative  property  of  amber  accounts,  in  some  measure,  for 
the  estimation  in  which  it  is  held. 

There  is  evidence  of  the  extreme  antiquity  of  amber  in 
the  fact  that  the  Phoenicians  imported  it  from  Prussia. 
Since  that  period  it  has  been  obtained  there  uninterruptedly, 
and  no  diminution  in  the  quantity  annually  collected  has 
been  perceived.  If  we  incline  to  the  theory  that  amber  is 
a  species  of  wax  or  fat,  having  undergone  a  slow  process 
of  putrefaction,  based  on  the  fact  that  chemists  are  able  to 
convert  ceraceous  or  fatty  substances  into  succinic  acid,  by 
inducing  oxidation  artificially,  the  belief  must  be  enter- 
tained that  a  new  formation  of  amber  is  constantly  going 
on,  which  theory  is  strengthened  by  the  different  appear- 
ance of  the  varieties  of  amber,  which  seem  to  exhibit  the 
successive  stages  of  its  development  and  decay.  On  the 
other  hand,  Tacitus,  in  his  Germania,  states  that  it  is  a  resin, 
exuded  by  certain  conifers,  traces  of  which  are  frequently 
observed  among  the  amber.  Certain  it  is  that,  at  one 
time,  amber  must  have  been  liquid,  from  the  simple  fact 
that  numerous  small  animals  are  found  inclosed  within  it ; 
these,  for  the  most  part,  are  insects  belonging  to  an  extinct 
species  of  arachnidse.  A  specimen  containing  the  leg  of 
a  toad  was  seen  among  an  extensive  collection  at  the  Lon- 


AMBER.  351 

don  Exhibition,  and  it  is  said  that  in  China,  amber  contain- 
ing  insects  is  of  frequent  occurrence.  From  the  fact  that 
amber  and  fossil  wood  have  been  found  in  alluvial  deposits 
of  sand  and  clay,  and  associated  with  ocean  shale  and  iron 
pyrites,  at  a  depth  of  sixty  feet,  it  is  the  author's  firm  be- 
lief that  the  marine  amber  is  a  subsequent  formation  to  the 
terrestrial  amber.  That  Pliny  already  took  it  for  a  vege- 
table production,  may  be  inferred  from  his  expression : 
"  quod  arboris  succura,  prisci  nostri  credidere." 

The  different  kinds  of  amber  are  distinguished  by  varie- 
ties of  color  and  degrees  of  transparency.  All  shades  of 
yellow,  from  the  palest  primrose  to  the  deepest  orange,  or 
even  brown,  are  its  constant  colors.  In  point  of  clearness, 
amber  varies  from  vitreous  transparency  to  perfect  opacity; 
some  are  nearly  as  white  as  ivory,  which  is,  however,  a  rare 
occurrence.  If  there  are  two  layers  together,  the  trans- 
parent and  opaque  varieties,  it  is  used  for  cutting  cameos. 
An  inquiry  naturally  suggests  itself  as  to  which  of  these 
varieties  of  amber  is  the  most  valuable.  It  is  self-evident 
that  this  must  depend,  as  in  the  diamond,  upon  the  size  and 
the  uniformity  of  the  pieces.  Besides,  as  all  varieties  ex- 
cepting the  white,  which  has  its  special  uses,  are  equally 
applicable  for  manufacturing  purposes,  it  follows  that  the 
value  of  any  particular  sort  must  depend  in  a  great  measure 
upon  its  variety.  The  straw-yellow,  slightly  translucent 
variety  is  the  most  rare,  and  is  that  which  the  Orientals 
prefer  to  all  others,  and  which  they  purchase  at  extrava- 
gant prices.  Every  piece  of  that  quality  is  exported  to 
Turkey,  in  the  raw  or  manufactured  state. 

Among  the  exquisite  specimens  of  amber  in  the  London 
Crystal  Palace,  were  four  most  splendid  imaums,  or  round 
amber  mouth-pieces,  richly  ornamented  with  brilliants ;  the 
shortest  two,  which  in  smoking  are  pressed  against  the 
lips,  were  each  worth  three  hundred  pounds  sterling,  and 


352  A   POPULAR   TREATISE    ON    GEMS. 

were  each  of  that  peculiar  color  and  degree  of  transparency 
which  approaches  nearest  to  the  Turkish  ideal  of  beauty. 
The  two  longer  mouth-pieces  were  of  a  different  form,  and 
although  not  of  so  good  a  color,  nor  enriched  with  as  many 
diamonds,  were  still  valued  at  two  hundred  pounds  sterling 
each. 

A  large  specimen  obtained  from  the  amber  pits  in  Prus- 
sia, weighing  six  pounds,  and  another  marine  amBer  and 
waterworn,  weighing  four  and  a  half  pounds,  owned  by  Mr. 
Wolff  Manheimer,  of  Konigsberg,  Prussia,  were  likewise 
at  the  London  Exhibition. 

At  the  Royal  Museum  in  Berlin,  is  a  large  mass  of  amber, 
weighing  eighteen  pounds. 

In  the  kingdom  of  Ava,  a  mass  nearly  as  large  as  a 
child's  head  was  found  some  years  ago,  which  was  inter- 
sected in  various  directions  by  veins  of  crystallized  carbon- 
ate of  lime. 

Amber  is  very  fusible  and  liable  to  be  broken.  To  join 
the  broken  pieces,  and  to  unite  them  in  such  a  manner  as 
to  look  and  wear  as  well  as  new,  the  author  of  this  treatise 
recommends  the  use  of  soluble  glass  (either  the  silicate  of 
soda,  or  silicate  of  potash),  which  is  applied  to  the  fissure 
or  fractured  part,  after  which  the  united  parts  are  tied  with 
with  a  twine  and  kept  so  for  some  days ;  it  will  then  remain 
firm.  Thick  shellac  varnish  is  also  highly  recommended : 
dissolve  bleached  shellac  in  ninety-five  per  cent,  alcohol, 
to  the  consistency  of  syrup,  touch  the  broken  parts  with 
the  varnish,  tie  them  with  twine,  and  leave  the  article  in 
a  warm  place  for  some  days  before  using. 

Amber  powder  made  into  a  paste  with  thick  shellac 
varnish  and  moulded,  may  easily  be  made  into  a  variety  of 
forms,  and  represent  genuine  amber. 

The  most  extraordinary  collection  of  specimens  of  amber 
may  be  seen  in  the  cabinet  at  Dantzic.  A  specimen  of 


JET.  353 

amber  of  fifteen  pounds  weight  is  preserved  in  the  cabinet 
at  Berlin.  The  inhabitants  of  Colberg,  in  1576,  presented 
to  the  Emperor  Rudolph  II.  a  specimen  weighing  eleven 
pounds. 

JET. 

This  mineral  occurs  massive ;  has  a  conchoidal  fracture ; 
is  opaque;  has  a  shining  lustre;  and  is  of  a  jet,  or  pitch- 
black  color.  It  is  pretty  soft,  and  yields  to  the  knife ; 
its  hardness  is  1*  to  2*5;  specific  gravity,  1*29  to  1*35; 
it  burns  with  a  greenish  flame,  and  emits  a  strong  bitumin- 
ous smell.  In  trade  it  is  also  called  black  amber,  or  pitch 
coal.  It  is  found  in  the  brown-coal  formation,  the  plas- 
tic clay,  and  the  lias,  with  lignite  and  amber,  in  England, 
France,  Silesia,  Hesse,  Italy,  Spain,  and  Prussia. 

Jet  bears  a  high  polish,  and  is  wrought  into  necklaces, 
ear-rings,  crosses,  rosaries,  snuff-boxes,  buttons,  bracelets, 
and  particularly  mourning  jewelry.  It  is  at  first  generally 
assorted  to  select  the  best  pieces,  most  suitable  for  working ; 
such  as  are  free  from  iron  pyrites,  lignite,  and  have  no 
cracks  or  fissures.  It  is  then  turned  on  a  lathe,  and  like- 
wise on  horizontal  sandstone  wheels,  which  run  unequally 
on  their  periphery,  by  which  the  various  specimens  may  be 
cut  and  polished  at  the  same  time.  During  the  operation 
the  jet  must  be  moistened  with  water,  else  it  may  crack 
from  being  overheated.  It  is  polished  with  rotten-stone  or 
crocus  martis  and  oil,  on  linen  or  buckskin ;  and  lastly  by 
the  palm  of  the  hand. 

The  manufacturing  of  jet  ornaments  was  formerly  a  con- 
siderable branch  of  industry  in  France,  where,  in  1786,  the 
department  de  PAube  occupied  twelve  hundred  workmen  ; 
but  at  the  present  time  it  is  not  worn,  and  the  black  enamel 
is  substituted  for  it. 

Jet  is  a  species  of  bituminous  coal,  which  has  several 


354          A  POPULAR  TREATISE  ON  GEMS. 

names,  such  as  common  coal,  black  coal,  cherry  coal,  splint 
coal,  cannel  coal,  jet,  lignite,  &c.;  more  properly,  how- 
ever, it  is  a  variety  of  cannel  coal,  but  it  is  much  blacker, 
and  has  a  more  brilliant  lustre.  It  occurs  in  detached 
pieces,  in  clay,  on  the  coast  near  Whitby,  in  Yorkshire, 
and  is  the  gagates  of  Dioscorides  and  Pliny,  a  name  de- 
rived from  the  river  Gagas,  in  Syria,  near  the  mouth  of 
which  it  was  found. 

Cannel  coal,  which  comes  nearest  to  jet,  has  a  dark- 
grayish,  black,  or  brownish-black  color,  a  large  conchoid al 
fracture,  and  receives  a  good  polish ;  takes  fire  readily,  and 
bums  without  melting,  with  a  clear  yellow  flame.  On  this 
account  it  has  been  used  as  a  substitute  for  candles,  and 
hence  receives  its  name.  It  is  very  abundant  in  Scotland, 
and  in  several  parts  of  Ayrshire ;  is  wrought  into  inkstands, 
snuff-boxes,  and  other  similar  articles.  In  England  the 
bituminous  coal  trade  is  a  large  traffic ;  over  one  hundred 
thousand  people  are  engaged  in  Newcastle,  in  digging. 
The  principal  coal  mines  of  France  are  those  of  St.  Etienne, 
Mons,  Charleroi,  and  Liege.  Germany  has  some  coal ;  but 
Belgium,  Norway,  Denmark,  and  Russia  seem  to  be  entirely 
destitute  of  coal  beds.  Some  few  beds  are  found  in  the 
Apennines,  in  Italy.  In  Spain,  coal  occurs  in  Andalusia, 
Aragon,  Estremadura,  Catalonia,  Castile,  and  the  Astu- 
rias,  but  not  in  large  quantities.  The  only  coal  bed  in  Por- 
tugal which  is  worked,  is  situated  in  the  province  of  Beira. 
Coal  is  also  abundant  in  China,  Japan,  the  island  of  Mada- 
gascar, Africa,  and  New  Holland.  But  nowhere  are  its 
deposits  more  extensive  and  numerous  than  in  the  United 
States.  It  occurs  extensively  throughout  the  Middle  and 
Western  States.  The  great  coal  formation  in  the  United 
States  is  one  of  its  principal  and  most  striking  geological 
features,  and  in  its  influence  upon  our  industrial  pursuits, 
it  is  unquestionably  the  most  important  of  all.  The  coal 


JET.  355 

measures  are  distributed  over  two  principal  areas,  termed 
the  gre%t  eastern  and  the  great  western  coal  fields,  being 
separated  from  each  other  by  a  wide  area  of  older  forma- 
tions. The  eastern,  or  Alleghany  coal  field,  may  be  traced 
from  near  the  northern  limit  of  Pennsylvania  to  the  south- 
west, in  a  line  parallel  with  the  Alleghany  chain,  quite  to 
the  central  part  of  the  State  of  Alabama.  The  anthracite 
basins,  which  are  of  comparatively  small  extent,  lie  beyond, 
or  to  the  east  of  the  line  here  traced  as  the  limits  of  the 
great  eastern  coal  field. 

From  its  northeasterly  margin  it  is  traced  along  a  veiy 
irregular  outline,  as  far  as  the  Alleghany  river,  in  Warren 
county,  Pennsylvania,  and  from  thence  it  follows  a  direction 
nearly  parallel  to  the  shore  of  Lake  Erie,  to  Portage  and 
Summit  counties,  in  the  State  of  Ohio.  From  thence  it 
follows  a  line  generally  parallel  to  its  eastern  margin,  though 
gradually  converging  to  its  southern  extremity,  in  Alabama. 
Tli is  coal  field  has  a  length  of  more  than  seven  hundred 
and  fifty  miles,  and  an  extreme  breadth  of  one  hundred 
and  eighty  miles.  The  superficial  area  has  been  estimated 
by  Richard  C.  Taylor  to  be  sixty-five  thousand  square 
miles ;  and  when  we  consider  the  aggregate  thickness  of 
the  different  beds  of  coal  over  this  wide  extent,  the  ag- 
gregate amount  of  fossil  fuel  appears  indeed  incompre- 
hensible. 

The  great  western  coal  field,  or,  as  it  has  been  usually 
termed,  the  Illinois  coal  field,  occupies  the  larger  part  of 
the  State  of  Illinois,  and  parts  of  Indiana  and  Kentucky. 
It  is  separated  only  by  a  narrow  belt  of  the  lower  forma- 
tions, along  the  Mississippi  valley,  from  the  coal  fields  of  Iowa 
and  Missouri,  the  extent  of  which  has  lately  been  shown 
to  be  much  greater  than  had  been  supposed.  Including 
the  parts  of  this  field  on  both  sides  of  the  Mississippi  river, 
its  greatest  extent  from  southeast  to  northwest,  or  from 


356  A  POPULAR  TREATISE  ON  GEMS. 

the  headwaters  of  Green  river,  in  Kentucky,  to  its  northern 
limit,  on  the  Desmoines  river,  in  Iowa,  is  more  than  five 
hundred  miles ;  while  its  greatest  breadth  across  the  States 
of  Indiana,  Illinois,  and  Missouri,  is  more  than  four  hun- 
dred miles,  and  from  its  northern  termination  in  Iowa  to 
its  present  known  limits,  on  the  Osage  river,  at  the  south, 
is  more  than  three  hundred  miles.  This  western  coal  field, 
therefore,  including  the  area  thus  occupied  on  both  sides  of 
the  Mississippi  river,  has  a  much  greater  superficial  extent 
than  the  eastern  coal  field,  already  described.  Perhaps 
the  entire  area  may  be  estimated  at  one  and  a  half  that  of 
the  Alleghany  coal  field,  or  nearly  one  hundred  thousand 
square  miles.  Still  farther  to  the  south,  in  Arkansas,  there 
is  a  coal  field  of  considerable  extent,  which  has  not  yet 
been  fully  explored ;  it  is  probably  connected  with  the 
Missouri  field. 

There  are  coal  fields  in  Michigan,  Rhode  Island,  and 
Massachusetts,  Eastern  Virginia,  North  Carolina,  near  Fort 
Laramie,  Puget's  Sound,  and  Bellingham  Bay. 

The  entire  area  occupied  by  coal  measures  in  the  United 
States,  east  of  the  Rocky  Mountains,  is  about  two  hundred 
thousand  square  miles. 

The  quantity  of  bituminous  and  anthracite  coal  consumed 
in  the  United  States,  may  be  estimated  at  fifteen  millions 
of  tons  annually. 

The  jet  of  Whitby,  in  Scotland,  forms  part  of  a  thick 
bed  of  lignite  found  there  in  the  upper  lias  marls ;  it  differs 
in  this  respect  from  the  jet  worked  in  France  and  Spain, 
which  is  found  in  irregular  veins  in  the  lower  marls  of  the 
cretaceous  series. 

Cannel  coal  is  chiefly  used  in  the  manufacture  of  gas, 
but  some  of  the  harder  and  more  compact  kinds  are  oc- 
casionally cut  into  various  ornamental  objects,  several  of 
which  were  represented  in  the  London  Exhibition ;  the  most 


MEERSCHAUM.  357 

interesting  of  these,  as  a  finished  work,  well  designed  and 
well  executed,  was  a  garden  seat,  from  the  parrot  coal,  in 
the  Fifeshire  coal  field,  exhibited  by  His  Royal  Highness, 
Prince  Albert ;  also  a  model  of  the  Durham  Monument, 
and  a  wine-cooler,  both  of  which  were  wrought  from  the 
Newcastle  coal  field.  A  set  of  chessmen  and  a  snuff-box, 
both  made  of  cannel  coal  from  China,  were  exhibited.  In 
Roman  Catholic  countries,  a  large  quantity  of  small  orna- 
ments, such  as  crosses,  beads,  rosaries,  <fcc.,  are  made  of  jet, 
and  it  is  generally  worn  for  mourning  decorations. 

In  regard  to  the  comparative  extent  of  the  coal  fields  of 
Great  Britain  and  the  United  States,  it  may  be  stated  that 
the  former  comprise  five  thousand  four  hundred  square 
miles,  while  those  of  the  United  States  contain  one  hundred 
and  ninety-six  thousand  eight  hundred  and  fifty  square 
miles.  The  amount  of  workable  coal  in  Great  Britain  is  put 
down  at  190,000,000,000  tons,  while  that  of  the  United 
States  is  set  down  at  4,000,000,000,000  tons,  or  twenty-two 
times  greater  in  amount  than  the  mines  of  Great  Britain ; 
and  it  is  well  worthy  the  reflection  of  political  economists, 
if  we  consider  what  has  been  achieved  by  the  produce 
of  the  coal  fields  of  Great  Britain,  what  revenue  must,  at 
a  future  day,  accrue  to  the  inhabitants  of  the  United  States 
from  their  vast  coal  fields. 


MEERSCHAUM. 

This  mineral  is  of  somewhat  rare  occurrence.  It  is  a 
hydrous  silicate  of  magnesia;  has  an  earthy  fracture,  opaque, 
dull,  smooth  surface ;  color,  white,  inclining  to  yellow,  red, 
or  gray ;  streak,  shining ;  adheres  to  the  tongue ;  has  a 
hardness  of  2*5,  and  a  specific  gravity  fcf  1'2  to  1'6.  If 
heated  in  a  matrass,  it  yields  water  and  turns  black.  Be- 
fore the  blowpipe,  it  melts  on  the  edges;  with  a  solution  of 


358  A  POPULAR  TREATISE   ON   GEMS. 

cobalt  becomes  red,  and  is  decomposed  by  hydrochloric 
acid. 

It  is  found  in  nodules,  at  Kiltschiek,  near  Conian,  in  Na- 
tolia,  in  a  large  fissure,  six  feet  wide,  in  calcareous  earth ; 
near  Thebes,  and  in  many  other  parts  of  Greece ;  Vallecas, 
near  Madrid,  and  Cavaiias,  near  Toledo ;  Pinheiro,  in  Por- 
tugal ;  Hrubschitz  and  Osbowern,  in  Moravia,  and  in  Swe- 
den ;  but  by  far  the  largest  quantity  is  derived  from  the 
peninsula  of  Natolia,  in  Asia  Minor.  It  is  called  meer- 
schaum, or  ecume  de  mer,  on  account  of  the  belief  of  the 
workmen  engaged  in  digging  the  mineral,  that  it  grows 
again  in  the  fissures  of  the  rock,  and  that  it  puffs  itself  up 
like  froth.  Good  meerschaum  is  tolerably  soft ;  resists  the 
pressure  of  the  hand,  but  is  easily  indented  by  the  finger 
nail,  and  especially  after  having  been  wetted ;  it  may  be 
easily  cut  with  a  knife. 

Although  the  fracture  is  earthy,  and  rarely  conchoidal, 
still  the  state  of  aggregation  of  pure  meerschaum  is  very 
variable,  as  is  proved  by  the  marked  difference  in  the  spe- 
cific gravity.  Some  kinds  sink  in  water,  others  float  on 
its  surface ;  and  these  qualities  are,  in  the  estimation  of  the 
pipe-maker,  indicative  of  different  values,  for  he  rejects 
both  the  very  heavy  and  the  very  light,  and  prefers  those 
of  medium  density.  The  light  varieties  are  generally  very 
porous,  and  even  contain  large  cavities,  whilst  the  heavier 
kinds  are  suspected  to  be  an  artificial  product.  Formerly, 
the  material  was  roughly  fashioned,  on  the  spot,  into  bowls, 
which  were  elegantly  carved  in  Europe.  The  art  was  spe- 
cially cultivated  at  Pesth  and  Vienna,  where  it  formed  an 
extensive  and  important  branch  of  trade.  These  rough 
bowls  still  occur  in  commerce ;  but  by  far  the  greater  part 
of  the  meerschaum  is  exported  in  the  shape  of  irregular 
blocks,  with  obtuse  angles  and  edges,  requiring  careful 
manipulation,  with  the  aid  of  water,  in  order  to  remove 


MEERSCHAUM.  359 

irregularities  and  faulty  portions.  This  preliminary  treat- 
ment still  leaves  numerous  blemishes.  The  meerschaum  of 
commerce  has  defects  of  various  kinds ;  besides  various 
minerals  scattered  through  its  mass,  it  contains  a  hard  sort 
of  meerschaum,  which  the  manufacturers  call  chalk,  and 
which  is  the  cause  of  much  difficulty  in  the  carving.  Pre- 
vious to  the  mechanical  treatment  of  the  meerschaum  for 
making  the  bowl,  it  is  subjected  to  a  certain  preparation. 
It  is  soaked  in  a  liquified  unguent,  composed  of  wax,  oil, 
and  fat ;  the  wax  and  the  fat  which  the  substance  absorbs, 
cause  the  colors  which  meerschaum  assumes  after  smoking. 
Under  the  influence  of  the  heat  produced  by  the  burning 
tobacco,  the  wax  and  fat  pass  through  all  the  stages  of  a 
true  process  of  dry  distillation ;  the  substances  thus  formed 
become  associated  with  the  products  of  the  distillation  of 
the  tobacco,  and  by  their  diffusion  through  the  meerschaum, 
all  those  gradations  of  color  which  are  so  highly  prized  by 
the  connoisseur,  are  produced. 

Occasionally,  though  rarely,  the  bowls  are  artificially 
stained,  by  steeping  them,  before  they  are  soaked  in  wax, 
in  a  solution  of  copperas,  either  alone  or  with  dragon's 
blood.  This  process  must  manifestly  very  materially  affect 
the  shade  of  color  produced  in  smoking. 

The  large  quantity  of  meerschaum  parings  left  in  rough- 
ing out  the  bowls,  would  entail  considerable  loss,  unless 
some  process  had  been  devised  of  rendering  them  available. 
A  species  of  meerschaum  bowl  has  long  been  known  in 
commerce,  under  the  name  of  massa  bowls,  which  is  made 
from  the  parings.  They  are  triturated  to  a  fine  powder, 
boiled  in  water,  and  moulded  into  blocks,  with  or  without 
the  addition  of  clay.  Each  of  these  blocks  suffices  for  one 
bowl ;  but  before  they  can  be  used,  they  must  be  allowed 
to  dry  for  some  time,  as  they  contract  considerably.  These 
bowls  are  distinguished  from  real  meerschaum  by  their 


360  A   POPULAR    TREATISE   ON   GEMS. 

greater  specific  gravity ;  but  there  is  no  very  certain  test  by 
which  the  real  meerschaum  can  be  distinguished  from  the 
composition,  and  many  suppose  that  all  the  heavier  descrip- 
tions are  spurious,  though  there  is  no  absolute  proof  of 
this  being  the  case.  A  negative  test  may,  however,  be 
mentioned :  the  composition  bowls  never  exhibit  those  little 
blemishes  which  result  from  the  presence  of  foreign  bodies 
in  the  natural  meerschaum ;  therefore,  if  a  blemish  occur 
in  a  meerschaum  bowl  (which  is  frequently  the  case),  the 
genuineness  of  the  bowl  is  rendered  more  probable ;  but  as 
these  do  not  show  until  after  the  bowl  has  been  used  for 
some  time,  the  test  is  not  of  much  value. 

Very  extensive  and  valuable  collections  of  meerschaum 
pipes  and  mouth-pieces  were  exhibited  in  the  London  Crys- 
tal Palace,  from  Gotha,  of  both  real  and  imitation  meer- 
schaum bowls.  From  Turin,  Sardinia,  were  elaborately- 
carved  meerschaum  pipe-bowls,  the  sculpturing  of  which 
was  very  exquisite.  From  Austria  a  large  collection  of 
massa  pipe-bowls  and  cigar-tubes,  which  were  manufactured 
from  meerschaum  dust ;  the  former  of  these  articles  was 
elegant,  and  the  execution  so  good,  that  they  were  with 
difficulty  distinguished  from  the  real  meerschaum. 

The  importation  of  meerschaum  pipes  and  cigar-tubes 
into  the  United  States  has  of  late  become  very  extensive, 
and  it  was  estimated  at  two  hundred  thousand  dollars  the 
last  year. 

LAVA. 

This  mineral  is  a  compound  of  several  minerals,  and  is  a 
volcanic  production.  It  occurs  massive,  with  vesicular  or 
porous  marks ;  has  a  splintery  and  conchoidal  fracture ;  a 
lustre  dull  or  glistening ;  is  opaque,  and  of  gray,  brown, 
red,  yellow,  black,  green,  and  white  colors,  of  all  their 
shades.  It  often  contains  crystals  of  felspar,  leucite, 


JADE.  361 

hornblende,  &c.  In  the  arts,  for  ornamental  purposes,  the 
compact  varieties,  only,  are  cut  and  polished.  In  Naples, 
jewelry  and  ornaments  in  great  quantities  are  manufactured 
and  exported ;  such  as  pins,  ear-rings,  intaglios,  snuff-boxes,' 
vases,  candelabras,  &c.  The  different  lavas  are  cut  with 
sand  and  emery,  and  polished  with  pumice-stone.  Lava  is 
found  in  all  volcanic  countries,  and  particularly  at  Etna, 
Vesuvius,  Hecla,  in  Mexico,  the  Lipari  Islands,  <fcc.  Lava 
is  often  used  as  the  base  for  mosaic  works.  The  blue  lava 
of  Mount  Vesuvius  has  the  appearance  of  artificial  blue- 
enamel,  and  is  in  much  demand  for  jewelry  and  ornaments. 
I  have  inspected  fine  specimens  of  polished  slabs  at  the 
rooms  of  the  Boston  Society  of  Natural  History. 


JADE. 

This  mineral  is  called,  in  mineralogical  works,  nephrite, 
hatchet-stone,  punamu.  It  occurs  massive ;  has  a  splintery 
fracture ;  a  greasy  lustre  when  polished ;  it  is  translucent ; 
scratches  glass,  and  is  attacked  by  felspar ;  it  is  of  moun- 
tain-grass and  sea-green  colors ;  is  fusible  into  a  greenish 
glass ;  it  consists  of  silex,  lime,  alumina,  magnesia,  and  iron. 
It  was  originally  found  in  China ;  it  occurs  in  Egypt,  on 
the  Amazon  river,  in  an  island  in  New  Zealand, '  called 
Pavia  Punamu,  and  in  the  United  States  (Smithfield,  R.  I., 
and  Newbury,  Mass.),  of  a  sky-blue  color,  and  a  greenish 
and  reddish-gray  variety  at  Eastpn,  Pa. 

The  name  nephrite  is  derived  from  ve^pof,  a  kidney.  It 
was  supposed  to  be  a  cure  for  diseases  of  the  kidneys. 

It  is  used  for  snuff-boxes,  cups,  &c. ;  and  in  Turkey  it  is 
used  for  handles  to  sabres,  daggers,  and  hatchets.  Deities 
formed  of  it  have  frequently  been  excavated  from  ancient 
ruins.  Such  I  saw,  a  few  years  ago,  in  a  collection  of  In- 
dian curiosities  brought  from  Mexico. 
16 


362  A   POPULAR   TEEATISE   ON.  GEMS. 


SERPENTINE. 

This  mineral  derives  its  name  from  its  variegated  color, 
which  resembles  the  skin  of  a  serpent.  It  is  generally 
divided  into  two  varieties :  the  common,  or  opaque  serpen- 
tine ;  and  the  precious,  noble,  or  tmnslucent  serpentine. 

Serpentine  occurs  massive ;  the  common  is  occasionally 
crystallized  in  rhomboidal  crystals, — in  Norway,  New  Jer- 
sey, and  Pennsylvania ;  it  has  a  splintery,  uneven,  and  con- 
choidal  fracture ;  is  unctuous  to  the  touch ;  yields  to  the 
knife ;  its  colors  are  green  in  all  its  shades,  but  also  reddish 
and  grayish ;  hardness,  3 '4 ;  specific  gravity,  2*5  ;  is  infusi- 
ble before  the  blowpipe,  but  with  borax  dissolves  into  a 
transparent  glass.  It  does  not  belong  to  the  stratified 
rocks,  but  to  the  ophites  of  Brogniart,  and  is  mostly  asso- 
ciated with  granite,  gneiss ;  micaceous,  chlorite,  argillaceous 
schists,  and  limestone;  it  therefore  belongs  to  the  primi- 
tive formation. 

Serpentine,  for  richness  and  variety  of  colors,  exceeds  all 
other  rocks ;  and  it  abounds  all  over  the  globe,  in  large 
consolidated  masses.  The  finest  precious  serpentines  come 
from  Fahleen  and  Gulsjo,  in  Sweden,  the  Isle  of  Man,  the 
neighborhood  of  Portsay,  in  Aberdeenshire,  Corsica,  Sibe- 
ria, and  Saxony.  Common  serpentine  occurs  at  Lizzard 
Point,  in  Cornwall.  In  the  Alps  we  find  the  serpentine 
nine  thousand  feet  high ;  in  France,  the  mountains  of  Li- 
mousin ;  in  Spain,  Norway,  Sweden,  Scotland,  the  Shetland 
Isles,  England,  Italy,  Bohemia,  Saxony,  Bavaria,  and  Swit- 
zerland; in  the  United  States  we  find  it  all  along  the 
Atlantic  coast,  where  the  primary  rocks  are  found,  as  at 
Hoboken  (New  Jersey),  opposite  to  New  York  city,  War- 
wick (New  Jersey),  as  far  as  Maryland,  at  Bare  Hills, 
through  Pennsylvania,  Rhode  Island,  Connecticut,  Massa- 
chusetts, Vermont,  &c.  The  serpentine  beds  of  Massachu- 


SEKPENTTXE.  363 

• 

setts  are  inexhaustible.  In  Middlefield,  Massachusetts,  the 
bed  is  one  quarter  of  a  mile  in  breadth  and  six  miles  in 
length,  which  alone  would  be  sufficient  to  supply  the  whole 
world  with  a  valuable  material  for  ornamental  and  archi- 
tectural purposes.  There  are  beds  at  Westfield,  Blanford, 
Pelham,  Zoar,  Windsor,  Marlborough,  Cavendish,  and 
other  towns  in  Vermont.  Most  beautiful  specimens  are 
found  in  Newbury,  near  Newburyport ;  and  latterly  a  new 
locality  was  discovered  by  Dr.  Jackson,  in  Lynufield, 
Massachusetts. 

Serpentine  incloses  chromate  of  iron  in  the  Shetland 
Islands,  Maryland,  &c. ;  and  is  on  that  account  of  the 
highest  importance  to  the  artist. 

It  is  easily  wrought  on  lathes  into  various  articles ;  such  as 
snuff-boxes,  vases,  inkstands,  &c. ;  in  a  small  place  named 
Zoblitz,  in  Saxony,  several  hundred  persons  are  constantly 
employed  in  the  manufacture  of  boxes,  trinkets,  and  chim- 
ney-pieces. The  locality  at  Granada,  in  Spain,  has  supplied 
many  churches  and  palaces  of  Madrid  with  large  columns, 
and  other  ornaments.  It  is*  really  surprising  that  the  in- 
habitants of  those  districts  where  the  precious  serpentine 
is  found,  have  not  yet  employed  it  as  an  article  of  trade,  as 
the  quality  of  the  American  serpentine  is,  if  not  superior 
to  the  English  and  Spanish,  certainly  not  inferior  to  any 
hitherto  found  :  and  I  trust  that  the  day  is  not  far  distant 
when  our  parlors  will  be  embellished  with  mantel-pieces, 
tables,  and  mantel-ornaments,  made  of  it.  Candlesticks, 
mugs,  pitchers,  knife-handles,  fire-iron-stands,  jamb-hooks, 
and  many  other  domestic  articles,  might  be  formed  of  it, 
instead  of  silver-plated,  steel,  and  cast-iron  ware. 

Serpentine  is  often  associated  with  a  number  of  other 
minerals :  as,  «,  serpentine  with  talc ;  5,  serpentine  with 
diallage  or  schiller-spar ;  c,  serpentine  with  amianthus ;  d, 
serpentine  with  asbestos ;  e^  serpentine  with  garnets ;  /, 


364  A   POPULAR   TREATISE   ON   GEMS. 

% 

serpentine  with  actinolite,  &G.  That  variety  which  contains 
amianthus  in  a  layer,  is  sometimes  exceedingly  beautiful ; 
and  when  polished  has  the  appearance  of  satin  spar. 


MARBLE. 

This  is  a  carbonate  of  lime,  and  a  wide  range  of  minerals 
belong  to  this  class,  containing  substances  which  are  sub- 
servient to  architectural  and  ornamental  purposes ;  the 
author  intends,  therefore,  treating  this  subject  more  exten- 
sively and  giving  it  a  wider  range  than  other  common 
minerals,  and  to  copy  from  the  jury  report  of  the  London 
and  New  York  Exhibitions. 

The  primary  form  of  calcareous  spar  is  an  obtuse  rhom- 
bohedron,  with  a  great  many  secondary  forms;  has  a 
hardness  of  2'5  to  3'5 ;  specific  gravity,  2'5  to  2*7 ;  it  has 
a  vitreous  lustre,  also  earthy;  white  or  grayish-white 
streak  ;  color  usually  white,  with  a  great  variety  of  shades 
of  gray,  red,  green,  and  yellow,  also  brown  and  black ;  it 
is  transparent  and  opaque,  the  transparent  varieties  ex- 
hibit double  refraction  very  distinctly ;  fracture  usually 
conchoidal,  but  obtained  with  difficulty,  when  the  specimen 
is  crystalline.  It  is  composed  of  .lime  and  carbonic  acid, 
the  colored  varieties  often  contain,  in  addition,  small  por- 
tions of  iron,  silica,  magnesia,  alumina,  and  bitumen,  and 
acids  produce  a  brisk  effervescence ;  before  the  blowpipe 
it  is  infusible, — it  loses,  however,  its  carbonic  acid,  gives  out 
an  intense  light,  and  ultimately  is  reduced  to  pure  lime, 
or  quicklime. 

Calcareous  spar  appears  under  a  very  great  variety  of 
forms  and  aspects ;  a  great  many  species  have,  therefore, 
been  created  by  mineralogists. 

Iceland  spar  was  first  applied  to  a  transparent  crystal* 
lized  variety  from  Iceland,  where  it  was  found  in  a  cavity 


MARBLE.  365 

in  trap,  with  stilbite,  on  the  north  shore  of  Eskifiord,  on 
the  east  coast  of  Iceland ;  and  the  property  of  double  re- 
fraction was  first  observed  in  this  variety  of  carbonate  of 
lime. 

Oolite  consists  of  minute  spherical  particles  aggregated 
by  calcareous  cement,  so  as  to  produce  a  massive  structure 
and  nearly  earthy  appearance ;  it  occurs  in  extensive  beds, 
and  is  so  called  from  its  resemblance  to  the  roe  of  fish, 
from  wov,  the  egg. 

Pisolite,  or  pea-stone,  differs  from  oolite  in  the  larger 
size  of  its  particles,  which  are  composed  of  concentric  la- 
mina. 

Chalk  is  a  massive  opaque  variety,  usually  white,  and 
possessing  a  purely  earthy  aspect  and  absence  of  lustre,  it 
is  usually  much  softer  than  the  other  varieties  of  this 
species,  and  appears  to  consist  in  a  great  measure  of  an 
aggregation  of  fossils,  chiefly  infusorial. 

Tufa,  an  alluvial  deposit  from  calcareous  springs;  it 
has  a  very  porous  structure. 

Agaric  mineral,  or  rock  milk,  is  a  loose  friable  variety, 
deposited  from  waters  containing  carbonate  of  lime  in  so- 
lution, it  is  formed  about  lakes  whose  waters  are  impreg- 
nated with  lime  ;  also  in  fissures  in  limestone,  and  in  lime- 
stone caverns. 

Anthraconite,  or  stink-stone,  swine-stone,  which  is  found 
columnar,  granular,  and  compact,  of  various  shades,  emits 
a  fetid  odor  when  struck  with  the  hammer. 

Stalactites  are  pendant  masses  of  limestone,  formed  in 
limestone  caverns  by  the  percolation  of  Water,  holding 
lime  in  solution,  through  their  rocky  roofs ;  the  evaporation 
of  the  water  causes  the  deposition  of  the  lime,  and  thus,  in 
time,  columns  are  often  formed  extending  from  the  roof  to 
the  floor  of  a  cavern ;  the  water  which  drops  to  the  floor 
from  the  roof  also  evaporates  and  causes  the  formation  of  a 


366  A  POPULAR  TREATISE  ON  GEMS. 

layer  of  limestone  over  the  floor ;  this  variety  has  been 
called  stalagmite. 

Argentine  possesses  a  silvery-white  lustre  and  contains  a 
little  silica. 

Fontainebleau  limestone  Is  an  aggregate  of  secondary 
rhombohedrons,  containing,  mechanically  mingled,  large 
portions  of  sand ;  this  species  in  some  of  its  forms  is  very 
generally  diffused. 

Marble  includes  all  the  imperfectly  crystalline  and  earthy 
varieties  which  admit  of  a  high  polish ;  it  is  also  called 
granular  limestone,  or  statuary  marble,  which  forms  some- 
times entire  mountains ;  but  more  frequently  occurs  in  beds 
in  gneiss,  porphyry,  and  mica  slate.  The  world  has  been 
supplied  for  centuries  past  with  statuary  marble  from  the 
Carrara  beds  on  the  gulf  of  Genoa,  from  the  islands  of 
Paras,  Naxos,  and  Tenos ;  Pentillicus  and  Hymettus,  near 
Athens,  in  Greece,  and  Schlandens,  in  Tyrol. 

Calcareous  spar  is  the  principal  source  of  our  polished 
marbles,  the  material  for  sculpture,  quicklime,  for  artificial 
stone,  flux  for  smelting  ores,  &c.  A  peculiarly  fine-grained 
compact  variety  is  employed  in  lithography,  which  is  mostly 
imported  from  Bavaria,  under  the  name  of  lithographic 
stone.. 

Italy  is  pre-eminently  the  country  where  the  manufac- 
ture of  marble  has  been  found  most  congenial  to  the 
artistic  feeling  of  the  mass  of  the  people,  and  there,  or  in 
its  vicinity,  at  the  present  day,  a  large  part  of  the  best 
marbles  used  in  central  Europe  are  obtained  and  worked. 
Of  late  years,  however,  France,  Spain,  Portugal,  and  parts 
of  Germany  and  Belgium,  have  employed  for  their  own  use 
and  in  their  own  style,  many  useful  and  valuable  marbles 
with  which  they  abound,  and  in  England  manufactories 
have  arisen,  at  first  and  chiefly  in  Derbyshire,  but  also  in 
Devonshire  and  Cornwall,  in  which  much  has  been  done  to 


MARBLE.  367 

raise  the  character  of  marble  decoration,  by  employing  the 
excellent  material  which  abounds  in  those  places,  and  by 
introducing  various  useful  objects  of  house-decoration  at  a 
price  which,  though  somewhat  too  High  for  the  mass  of 
consumers,  is  far  below  that  of  foreign  goods  of  the  same 
kind  in  that  country.  Ireland,  also,  in  which  several  fine 
marbles  occur,  has  given  proof  of  some  activity  in  this 
manufacture,  for  which,  indeed,  nature  has  afforded  many 
facilities  to  carry  out  to  full  advantage. 

Many  marbles  from  Greece,  Italy,  and  the  coast  of  Asia 
Minor,  were  used  Jby  the  ancients,  but  the  quarries  are  now 
exhausted  or  concealed  by  rubbish.  Among  them  may  be 
mentioned  the  true  Parian  of  Greek  sculptors,  and  some 
other  fine  white  marbles ;  the  nero  antico,  now  a  very  rare 
black  marble,  considered  purer  and  better  than  the  known 
kinds ;  the  rosso  antico,  a  deep  blood-red  marble  with  veins 
and  spots;  the  verde  antico,  a  green  and  very  beautiful 
porphyritic  breccia ;  the  giallo  antico,  not  unlike  the  modern 
Sienna  marble,  of  very  rich  yellow  tint,  with  some  others. 
Most  of  these  are  only  known  in  sculptured  specimens ;  but 
many,  if  not  all  the  colors  are  closely  approximated  by 
recent  marbles. 

The  French  marbles,  those  illustrating  the  Pyrenees  and 
Vosges,  were  not  less  interesting.  Messrs.  Derville  ex- 
hibited one  hundred  slabs  of  marble,  each  sixteen  inches  in 
height,  comprising  twenty  varieties,  and  among  them  the 
marble  called  "  girotte"  (spotted  with  red  and  brown),  and 
the  -white  marble  of  St.  Beat,  all  remarkable  for  the  rarity 
of  their  colors  and  the  beauty  of  their  polish.  The  Campan 
marbles  also  possess  a  peculiar  geological  interest  in  the 
number  of  goniatites  which  they  inclose  and  which  are 
often  mixed  confusedly  with  the  paste;  an  arrangement 
which  evidences  the  great  change  which  these  limestones 
have  undergone  at  some  period,  and  which  proves  their 


368  A  POPULAR  TREATISE  ON  GEMS. 

metamorphism,  like  the  limestones  of  the  State  of  New 
York. 

The  chief  marble  manufacture  of  England  is  in  a  part  of 
Derbyshire  remarkable  for  its  picturesque  beauty,  extend- 
ing along  the  valley  of  the  Derwent  and  its  principal 
tributary,  the  Wye,  from  below  Buxton  to  Derby. 

The  machinery  for  sawing  and  polishing  was  first  estab- 
lished at  Derbyshire  at  the  village  of  Ashford,  near  Bake- 
well,  in  the  year  1748,  water  being  the  motive  power;  in 
1810,  similar  machinery  was  erected  in  Bakewell,  and  for 
many  years  past,  also,  in  Derby. 

The  most  important  marbles  of  Derbyshire  are  the  black, 
the  rosewood,  the  encrinital,  the  russet  or  bird's  eye,  and  a 
mottled  dark  and  light  gray  kind,  occasionally  containing 
numerous  small  corals.  Of  some  of  these  there  are  several 
varieties.  Others  might  be  added  to  the  list  of  those 
found  in  the  northern  part  of  the  county,  one  of  which 
is  a  beautiful  red,  resembling  the  rosso  antico,  but  it  is  ob- 
tained only  in  small  blocks  or  lumps. 

.  At  Welton,  in  Staffordshire,  near  the  borders  of  Derby- 
shire, are  marbles  differing  much  from  the  above,  but  they 
have  not  been  brought  into  any  considerable  use,  and  are 
generally  subject  to  flaws.  The  black  marble  is  of  very 
fine  color  and  texture,  but  large  slabs  free  from  small  veins 
of  calcareous  spar  are  rare  ;  the  best  quality  occurs  in  beds 
of  from  three  to  eight  inches  in  thickness,  some  beds  are 
thicker.  This  marble  is,  perhaps,  superior  to  the  similar 
kinds  found  in  other  parts  of  Europe  and  is  greatly  valued 
for  inlaying ;  it  is  tough  and  contains  a  good  deal  of  carbon, 
which  imparts  the  color. 

Black  marble  is  extensively  used  for  ornamental  objects, 
such  as  vases,  pedestals,  chimney-pieces,  &c.,  for  which  it 
is  admirably  adapted. 

Rosewood  marble  is  extremely  hard  and  of  close  texture ; 


MARBLE.  369 

the  beds  are  of  considerable  thickness,  but  the  most  beau- 
tiful part  of  the  ma'rble  ia  only  about  six  inches  thick ;  the 
name  is  derived  from  the  marking  of  the  marble  being 
somewhat  similar  to  that  of  rosewood. 

Encrinital  marble  is  the  one  in  most  extensive  use,  and 
contains  very  numerous  fossils,  consisting  almost  exclusively 
of  the  broken  fragments  of  encrinital  stems,  often  entangled 
in  coral ;  it  may  be  obtained  in  blocks  of  large  superfices 
and  of  a  thickness  of  two  to  two  and  a  half  feet. 

Russet,  or  bird's  eye,  takes  its  name  from  its  color  and 
appearance ;  the  shades  varying  from  light-gray  to  brown. 
It  contains  numerous  minute  fossils,  also  encrinital,  and  is 
found  in  beds  from  six  to  eighteen  inches  in  thickness. 

Dark  and  light  mottled  gray  marble,  called  Newburgh 
marble,  and  the  overlying  bed,  which  is  coralline,  can  be 
obtained  from  one  to  two  feet  thick. 

The  manufacture  of  Devonshire  marble  is  much  more 
modern,  and  the  material  is  generally  less  manageable. 
Almost  all  the  beautiful  marbles  of  that  county,  especially 
those  near  Plymouth,  are  fossiliferous,  brittle,  and  very  apt 
to  contain  veins  and  cracks.  The  marbles  of  Devonshire 
belong  to  an  older  geological  period  than  those  of  Derby- 
shire, the  latter  being  exclusively  of  the  carboniferous 
limestone  series,  underlying  the  coal  measures  and  mill- 
stone grit ;  while  the  former  are  of  the  devonian  or  middle 
paleozoic  epoch. 

Among  the  most  notable  marbles  in  the  London  Exhibi- 
tion, may  be  mentioned  the  following  articles:: 

Three  chimney-pieces  of  Carrara  marble,  with  many 
sculptured  figures,  from  Milan,  in  Italy  ^  columns  and 
pedestals  of  the  madrepore  marble,  from  a  quarry  in  Devon- 
shire ;  some  pedestals  of  green  marble,  from  Connemara, 
in  Ireland ;  a  table  belonging  to  the  East  India  Company 
was  exhibited,  the  top  of  which  consists  of  a  slice  of  a 


370  A  POPULAR  TREATISE  ON  GEMS. 

column  from  Nineveh;  several  slabs  of  the  Lumachella 
marble,  and  a  marble  called  verde  di  prato,  were  exhibited 
from  Tuscany,  which  were  extremely  beautiful.  A  bust  of 
Grattan,  of  Irish  marble  of  a  beautiful  yellow  color,  at- 
tracted much  attention. 

It  may  not  be  out  of  place  to  mention  here  the  extensive 
display  of  marble  statuary,  which  was  also  at  the  London 
Exhibition, — only  a  few  will  be  enumerated  for  want  of 
space : 

1.  Marble  statue  representing  Gratitude. 

2.  Group  representing  Eve  with  Cain  and  Abel  asleep  in 
her  arms. 

3.  Marble  statue  of  Susannah. 

4.  Iconic. statue  in  marble. 

5.  Marble  statue  of  Eve  after  the  Fall.  ^  . 

6.  Marble  statue  representing  the  Greek  Slave. 

7.  Marble  group  representing  Cephalus  and  Procris. 

8.  Marble   figure  representing  a  Boy  frightened  by  a 
Lizard. 

9.  Reclining  figure,  in  marble,  representing  Ishmael. 

10.  Marble  statue  of  a  Boy  catching  a  Butterfly;  also, 
a  marble  figure  representing  Arethusa. 

11.  Marble  statue  representing  Giotto. 

12.  Marble  statue  of  the   sculptor  Flaxman,  and  two 
statues  of  the  first   Lord  Eldon,   and  his  brother,  Lord 
Stowell. 

13.  Marble  group  of  a  Girl  with  a  Lamb,  representing 
Innocence. 

14.  Marble  statue  representing  a  Startled  Nymph. 

15.  Marble  figure  of  a  Bacchante. 

16.  Marble  statue  of  Dying  Gladiator. 

17.  Marble  group  representing  an  episode  in  the  history 
of  the  war  between  the  Amazons  and  the  Argonauts. 

18.  Marble  statue  of  Psyche.    % 


MAKBLE.  371 

19.  Marble  statue  representing  a  Girl  carrying  a  Nest  of 
Cupids. 

20.  Marble  statue  representing  Eurydice. 

21.  Marble  group,— "The  Orphans." 

22.  A  reclining  marble  figure  of  Bacchus. 

23.  Model  in  marble  of  a  Friar  presenting  the  Crucifix 
to  two  Children. 

24.  Marble  bust  of  the  poet,  Vincenzo  Monti. 

25.  Figure  in  marble  representing  Mary  Magdalen. 

26.  Marble  group, — Sleeping  Child  and  Dog. 

Italian  marble  furnished  the  material  from  which  most 
of  the  above  sculptures  were  wrought. 

The  United  States  limestones,  for  building  purposes,  and 
marble  for  statuary,  are  found  in  great  abundance,  and 
many  of  them  fairly  compare  with  the  Italian  and  English 
marbles.  The  white  granular  limestones  are  mined  in  many 
places ;  they  all  belong  to  the  newer  metamorphic  rocks, 
where  they  occupy  a  wide  range,  from  Vermont,  Massa- 
chusetts, Rhode  Island,  Connecticut,  New  York,  Pennsyl- 
vania, and  Maryland,  to  Missouri ;  but  the  best  statuary 
marble  has  as  yet  only  been  found  in  the  eastern  part 
of  Vermont:  100,000  cubic  feet  of  good  marble,  suitable 
for  building  stone,  mantel-pieces,  <fcc.,  have  been  mined 
annually  in  Vermont. 

The  character  of  the  white  marble  varies  from  finely 
granular  to  coarsely  crystalline,  and  from  a  compact,  close-" 
grained  mass  to  a  friable  crystalline  rock ;  they  all  derive 
their  existence  from  the  metamorphism  of  lower  silurian 
limestones.  The  whole  range  of  these  newer  metamorphic 
rocks,  from  Northern  Vermont  as  far  as  Maryland,  yield 
abundance  of  the  granular  limestone;  along  the  western 
slope  of  the  Green  iSIountain  range,  the  principal  localities 
are  Brandon,  Dorset,  Pittsford,  Rutland,  Middlebury, 
Pairhaven,  and  Sudbury,  in  Vermont ;  the  principal  quar- 


372  A  POPULAR  TREATISE  ON  GEMS. 

ries  in  Massachusetts  are  at  West  Stockbridge,  Egremont 
Groat  Harrington,  Lanesborough,  New  Ashford,  Sheffield, 
and  New  Marlborongh.  In  New  York,  marble  is  quarried 
in  large  quantities  at  Hastings  and  Sing  Sing,  and  Dover, 
in  Dutchess  county,  and  the  range  of  granular  limestones 
extends  through  Columbia,  Dutchess,  and  Putnam  coun- 
ties ;  and  in  Connecticut  the  same  granular  limestones  occur 
in  abundance;  also  in  New  Jersey,  a  few  miles  west  of 
Philadelphia,  and  near  Ilagerstown,  in  Maryland.  The 
marble  quarries  in  Rhode  Island,  Eastern  Massachusetts, 
and  Maine,  furnish  very  fine  marble,  belonging  to  the 
metamorphic  limestones  of  a  more  recent  date,  but  it  is  not 
as  durable  as  those  of  an  older  age ;  it  is  more  friable,  and 
has  more  fissures. 

Bird's-eye  or  encrinitaJ  marble  forms  an  extensive  bed  in 
the  State  of  New  York;  it  is  a  compact  crinoidal  lime- 
stone, containing  fragments  of  stems  and  joints  of  crinoids 
of  a  bright  pink,  and  other  organic  remains  of  a  dark 
color,  which,  on  the  gray  ground,  give  a  beautiful  variety. 
A  similar  limestone,  susceptible  of  receiving  a  polish,  occurs 
in  the  lower  bed  of  the  Niagara  limestone,  at  Lockport  and 
at  Becraft's  Mountain,  near  Hudson,  where  the  organic 
remains  are  nearly  similar  to  the  first.  Also  the  Onondaga 
limestone  affords  a  similar  marble,  and  taking  a  fine  polish, 
with  a  much  greater  variety  of  organic  remains  than  either 
pf  those  just  described.  All  these  limestones  compose  very 
thick  beds,  and  are  all  suitable  for  ornamental  purposes; 
they  are  a  very  excellent  and  durable  building-stone,  and 
are  extensively  used  for  the  massive  and  beautiful  locks  and 
piers  on  the  Erie  canal,  at  Lockport,  and  as  building-stone 
in  Buffalo,  Lockport,  and  Rochester,  and  the  city  hall  and 
court  house  in  Chicago  have  been  built  from  it ;  they  belong 
to  the  group  of  limestones  called  the  Niagara  group. 

On  a  recent  visit  to  Buffalo,  the  author's  special  attention 


MA-KBLE.  373 

was  directed  to  the  wide  range  of  marble,  beginning  at 
Harlem  Bridge,  New  York  island,  where  the  fine  white 
granular  marble  begins ;  crossing  thence  to  Hastings,  twen- 
ty miles  farther  up  the  Hudson  river,  of  a  still  finer,  and 
also  coarser  white  marble ;  farther  on,  the  Dutchess  county 
white  marble ;  and  gradually  coming  into  the  black  marble 
region  at  Schenectady.  At  Little  Falls,  high  cliffs  of 
that  species  of  limestone,  with  magnificent  scenery,  ex- 
cited his  admiration  on  passing  in  the  railroad  cars.  A 
short  visit  to  the  State  Cabinet  of  Geology  in  Albany 
gratified  him  in  the  extreme ;  and  every  person  desirous  of 
being  informed  of  the  vast  resources  of  limestone  of  the 
State  of  New  York,  cannot  spend  a  more  pleasant  or  in- 
structive day  than  to  examine  the  well-arranged  museum 
of  the  geological  formation  of  the  State  of  NewT  York,  and 
of  the  minerals  of  this  State  and  neighborhood. 

A  short  description  of  this  class  of  limestones  may  give 
the  reader  some  idea  of  the  intrinsic  value  of  the  results  of 
the  scientific -research,  accomplished  through  the  liberally 
extended  munificence  of  the  several  legislatures  of  the 
State,  by  such  men  as  Hall,  Eramons,  Conrad,  Mather,  and 
Yannuxem.  The  visitor  will  perceive,  on  the  entrance 
into  the  large  hall  of  the  Geological  Cabinet,  a  large  slab 
of  the  chalky  limestone,  with  the  thousand  ammonites  and 
orthoceratites  imbedded ;.  he  next  beholds  "the  bird's-eye 
limestone,  some  specimens  having  also  thousands  of  sharks' 
teeth  on  the  surface ;  he  next  sees  the  Black  river  and 
Trenton  limestone,  both  rough,  and  also  fine  polished  spe- 
cimens, inclosing  the  orthoceratite  in  its  polished  state,  as 
if  cut  in  two  parts,  and  it  makes  a  very  beautiful  appear- 
ance ;  the  Mohawk  valley  and  Hudson  river  group,  with 
all  the  imbedded  fossils,  next  attracts  his  attention ;  the 
Utica  slate  and  its  large  trilobites,  from  one  to  twelve 
inches  in  length,  along  with  the  Niagara  limestone  group, 


374  A  POPULAR  TREATISE  ON  GEMS. 

displaying  likewise  the  gigantic  trilobite  family,  is  not  less 
attractive  than  the  enormous  slab  of  the  black  limestone, 
called  the  corniferous  limestone,  with  the  Marcellus  shale, 
near  Manlius,  in  Onondaga  county.  This  slab  contains 
several  ammonites  of  one  foot  in  length;  it  is  called  now 
the '  ffoniatilis  expansus  orthoceratas  marcellinius.  This 
specimen  must  weigh  at  least  one  hundred  pounds,  and  is 
three  feet  in  length ;  and  it  is  certainly  a  very  magnificent 
specimen. 

The  large  rhombic  limestone,  from  St.  Lawrence  county, 
with  the  dogtooth  spar,  from  Lockport,  form  interesting 
specimens  in  the  mineralogical-  department  of  the  State 
Cabinet. 

The  splendid  quartz  crystals,  from  Herkimer  county  and 
Lake  George,  as  also  the  fluor  spar  of  Jefferson  county,  and 
the  beautiful  green  crystals  of  apatite,  from  St.  Lawrence 
county,  with  the  sulphate  of  strontia  specimens,  from  the 
latter,  Onondaga,  and  Schoharie  counties, — all  claim  their 
respective  merits ;  the  labrador  spar  and  hypersthene,  from 
Essex  county,  the  gypsum,  sulphate  of  baryta,  the  beauti- 
ful rose  quartz,  from  Fort  Henry,  the  red  sapphire  crystals, 
from  Orange  county,  and  the  amethysts,  intermixed  in 
layers  with  the  serpentine,  from  Putnam  county,  form  very 
fine  ornamental  minerals. 

Among  the  most  interesting  minerals  of  this  State  may 
be  mentioned  the  rensselaerite,  from  Fort  Edward  ;  a  great 
many  specimens  of  this  interesting  mineral,  both  rough 
and  polished,  may  be  seen  in  the  State  Cabinet.  It  forms 
irregular  masses  in  that  limestone  region,  has  an  unctuous 
feel  of  stalactite,  but  is  of  superior  hardness ;  resembles  more 
the  satin  spar  in  its  crystalline  form ;  it  resembles  pyroxene, 
but  differs  much  from  it  in  its  hardness  and  specific  grav- 
ity ;  its  hardne'ss  is  3'5  to  4',  and  specific  gravity  2'87 ;  its 
color  is  white,  yellowish-white ;  has  uneven  fracture.  This 


MARBLE.  375 

mineral  was  -named  in  honor  of  the  late  patroon,  Gen, 
Stephen  Van  Rensselaer,  of  Albany.  This  mineral  abounds 
in  St.  Lawrence  county,  and  will,  no  doubt,  at  no  distant 
day,  be  wrought  into  many  beautiful  ornaments ;  the  pol- 
ished specimens  in  the  State  Cabinet  are  very  fine. 

The  Potomac  and  breccia  marble  is  a  rock  of  the  newer 
red  sandstone  series ;  it  forms  a  beautiful  rock,  and  the  col- 
umns of  the  hall  of  the  House  of  Representatives,  at  Wash- 
ington, are  cut  from  this  somewhat  hard  material. 

The  serpentine  marble,  or  verd-antique,  occurs  in  nu- 
merous localities  along  the  belt  of  formations  which  extends 
from  northern  Vermont,  through  the  western  part  of 
Massachusetts,  Connecticut,  a  small  portion  of  southern 
New  York,  New  Jersey,-  Pennsylvania,  and  Maryland ; 
this  formation  is  metamorphic  of  a  part  of  the  Hudson 
river  group.  A  very  beautiful  verd-antique  marble  occurs 
at  Cavendish,  Lowell,  and  Troy,  in  Vermont ;  in  Cheshire, 
Massachusetts,  and  in  Milford,  Connecticut.  There  are 
two  kinds  of  verd-antique  marble — the  true  verd-antique, 
and  the  serpentine  marble;  the  first  occurs  in  Vermont 
and  Milford,  Connecticut,  and  the  latter,  called  the  com- 
mon, near  New  Haven,  Connecticut. 

The  white  coarse-grained  marble,  from  Texas,  Baltimore 
county,  Maryland,  is  quarried  very  extensively,  and  used 
in  Washington  City  for  the  capitol  extension,  treasury,  and 
post-office  department. 

In  Missouri  occur  large  beds  of  white  and  reddish-white 
marble,  in  Jefferson  county  and  near  St.  Louis ;  the  Gene- 
vieve  marble,  which  is  an  oolitic  limestone,  has  a  very 
extensive  formation,  and  is  used  in  St.  Louis  and  New 
Orleans  as  building-stone ;  some  marble  quarries  are  full 
of  organic  remains,  and  some  are  so  hard  and  durable  that 
they  are  used  for  hearths,  having  extraordinary  power  to 
resist  the  action  of  heat. 


376  A  POPULAR  TREATISE  ON  GEMS. 

•  Breccia  Marble,  of  Lancaster  county,  Pennsylvania. — 
This  is  a  recent  discovery  of  a  variegated  marble,  a  pure 
carbonate  of  lime,  and  differs  materially  from  other  mar- 
bles of  the  United  States  and  foreign  countries ;  and  an 
independent  name  has  been  given  to  it  by  its  discoverer, 
viz. :  the  leocadia  breccia,  which  forms  a  solid,  unstratified 
bed  of  compact  marble.  It  is  admirably  adapted  for  orna- 
menting churches,  banks,  hotels,  and  other  public  buildings, 
as  also  for  private  houses  for  mantels,  tables,  wainscoting, 
balustrades,  &c.  It  is  very  easily  wrought,  and  has,  there- 
fore, the  advantage  of  many  other  marbles  of  the  United 
States.  This  new  locality  bids  fair  to  drive  the  foreign  and 
more  costly  marbles  out  of  the  market ;  as  for  brilliancy  of 
color  and  its  variegated  character,  and  for  strength  and 
durability,  it  has  not  its  equal,  either  in  the  United  States 
or  any  foreign  country.  It  is  sincerely  to  be  hoped  that 
so  valuable  a  bed  of  limestone  may  not  be  left  slumbering 
for  another  century,  but  that  the  discoverer,  Mr.  James  -W. 
Hale,  may  reap  the  benefit  of  its  speedy  development  and 
general  application. 

The  New  York  Exhibition  of  1853  was  well  supplied 
with  statuary  from  the  whole  world,  but  -particularly  from 
Italy.  The  Italian  works  consisted  mostly  of  copies  from 
the  antique.  The  copy  of  the  Flora  of  the  Capitol;  Barto- 
lini's  Faith ;  Harpocrates,  and  Cupid  in  a  mischievous  niQod ; 
Canova's  Hebe,  and  Thorwaldsen's  statuary, — were  all  of 
great  merit.  Power's  statues  of  Eve  and  Proserpine  have 
been,  in  addition  to  the  Greek  Slave  and  Fisher-boy, 
already  noticed  among  the  great  curiosities  of  the  London 
Exhibition.  We  will  enumerate  the  other  statues  in  marble 
which  were  much  admired  at  the  New  York  Exhibition, 
viz. : 

1.  A  Bacchante,  and  Psyche,  from  the  sculptor,  Gait,  of 
Norfolk,  Va. 


MARBLE.  377 

2.  Bust  of  Daniel  Webster  ;  the  Husbandman's  Orphan, 
a  nude  figure  of  a  boy  leaning  on  a  spade ;  and  the  Sleep- 
ing Child, — all  in  marble,  by  Pietti,  New  York. 

3.  The  Minstrel's  Curse,  by  Miller,  New  York. 

4.  Christ  in  the  Sepulchre,  by  Creswell,  Brooklyn. 

5.  Bust  of  Dr.  John  Green,  of  South  Carolina,  and  one 
of  Charles  Allen,  of  Massachusetts,  by  Kinney,  of  Worces- 
ter, Massachusetts. 

6.  Head  of  a  Female,  by  Ives,  Connecticut. 

7.  Bust  of  Daniel  Webster,  by  King,  Boston. 

8.  A  veiled  Cupid,  by  Moon,  New  York. 

9.  Head  of  Jupiter,  and  statuettes,  by*Ferris  &  Taber, 
New  York. 

10.  Cupid,  and  Charity,  a  female  figure  seated,  with  an 
infant  in  her  arms,  life  size,  by  Baudel,  London. 

11.  Busts  of  Daniel  O'Connell  and  Father  Mathew,  from 
Hagan,  Dublin. 

12.  Bust  of  Jenny  Lind,  by  Durham,  London. 

13.  Bust  of  Palmerston,  by  Sharp,  London. 

14.  Ruth  and  Naomi,  by  Kirk,  Dublin. 

15.  Bust  of  Louis  Napoleon,  emperor  of  France,  by 
Deumier,  Paris. 

16.  Statue  of  Racine,  by  D'Angier,  Paris. 

17.  Lesbia,  by  L'Eveque,  Paris. 

18.  Damalis,  by  Etex,  Paris. 

19.  A  veiled  head  ;  a  sleeping  Cupid ;  Psyche  reposing, 
and  bust  of  Prayer,  by  De  Bokeleer,  Antwerp. 

20.  Statue  of  Venus  and  Cupid,  by  Fraikin;  Brussels. 

21.  Two  Children  Sleeping,  as  a  group,  by  Geess,  Brus- 
sels. 

22.  Hebe,  from  Canova,  by  Lazzerini,  Rome. 

23.  A  Danaide,  head  of  an  Amazon,  and  bust  of  Queefl 
Victoria,  by  Bariata,  Rome. 

24.  Iris,  by  Cartei,  Florence. 


378  A  POPULAR  TREATISE  ON  GEMS. 

25.  Hagar  and  Ishmael  in  the  Desert,  by  'Catelli,  Flor- 
ence. 

26.  Lord  Palmerston,  by  Fabrucci,  Florence. 

27.  Harpocrates,  the  God  of  Silence,  full  length  ;  and 
Cupid  in  a  mischievous  mood,  by  Santarelli,  Florence. 

28.  Statue  of  Truth,  a  tipsy  Bacchus,  and  Virgin  of  the 
of  the  Eucharist,  a  bas-relief;  by  Cambi,  Florence. 

29.  The  Betrothed,  and  the  Son  of  William  Tell,  by 
Romanelli,  Florence. 

30.  The  Genius  of  Sacred  Music,  and  Laura,  by  Consani, 
Florence. 

31.  The  Sleep  of  Innocence,  by  Dupri,  Florence. 

32.  John  the  Baptist  sleeping,  by  Magi,  Florence. 

33.  Death  of  Ferruccio,  by  Giampaoli,  Lucca. 

34.  Rebecca,  Faithful  Love,  the  Child's  First  Grief,  bust 
of  Cleopatra,  and  bust  of  Heloise,  by  Vaspi,  Florence. 

35.  The  Mendicant,  by  Strazza,  Rome. 

36.  Shepherdess   and   Bird,  the   Guardian   Angel,   and 
Psyche  sorrowing,  by  Bimaimi,  Rome. 

37.  Cupid  leaning  on  a  wine-skin,  by  Strechi,  Rome. 

38.  Cupid  with  the  arms  of  Mars,  the  Sacrifice  of  a  God, 
and  three  Female  Dancers,  by- Jerichau,  Rome. 

39.  Columbus,  Staffetti,  Carrara. 

40.  A  Bacchante,  a  nymph  wreathing  herself  with  flow- 
ers, the  Genius  of  Summer,  the  Genius  of  Spring,  Herminia 
writing  the  name  of  Tancred,  and  Poetry,  by  Pelliccia, 
Carrara. 

41.  Cupid,  Psyche,  and  Venus  of  the  Louvre,  by  Fabri- 
cotti,  Carrara. 

42.  The   Flora  of  the  Capitol,   Bartolini's  Faith,   the 
Dying  Gladiator,  bust  of  the  Saviour,  St.  John  the  Baptist, 
bust  of  Rousseau,  by  Baratta,  Carrara. 

43.  Pope  Pius  IX.,  by  Tenerasie,  Carrara. 

44.  Bust  of  Washington,  by  Bagazzi,  Carrara. 


MAKBLE.  379 

45.  Cop/of  the  Warwick  Vase,  Flora  of  the  Capitol,  the 
Pet  Bird,   Apollo   Belvidere,   Copernicus,   Diana  of  the 
Louvre,  Dante,  Jupiter,  Shakspeare,  Madonna,  and  Faith, 
by  Marchetti,  Carrara. 

46.  Marcus  Tullius  Cicero,  and  Paris,  by  Fontana,  Car- 
rara. 

47.  The  Shepherdess  and  Lamb;    a   Struggle  for  the 
Heart,  by  Orlandi,  Carrara. 

48.  Ceres,  Venus,  Child  with  a  Bird,  Psyche,  Poetry, 
and  Vincenzo  Gioberti,  by  Bruneri,  Turin. 

49.  The  Virgin  mourning  over  the  dead  body  of  Christ, 
by  Angero,  Turin. 

50.  The  Virgin  and  Angel  of  Annunciation,  by  Galeazzi, 
Turin. 

5 1 .  Hebe  offering  Nectar  to  the  Eagle,  by  Kachszman, 
Milan. 

52.  Boy  riding  on  a  Crawfish,  a  Tortoise,  Leda  with  the 
Swan,  Innocence,  and  veiled  head,  by  Croff,  Milan. 

53.  Atala  and  Chactas,  colossal  bust  of  the  Redeemer, 
by  Fraccardi,  Milan. 

54.  Infant  Saviour,  Child  on  the  Waves,  by  Galei,  Milan. 

55.  The  Deserted,  veiled  head,  Cupid  forcing  the  Roses, 
nest  of  Cupids,  cage  of  Cupids,  and  basket  of  Cupids,  by 
Motelli,  Milan. 

56.  Sleeping  Venus,  by  Rados,  Milan. 

57.  Resignation,  by  Tandardini,  Milan. 

58.  The  Fisher-boy,  by  Cacchi,  Milan. 

59.  The  Soldier's  Son,  by  Jorini,  Milan. 

60.  Head  of  the  Saviour,  and  colossal  bust  of  Vincenzo 
Monti,  by  Langiorgio,  Milan. 

61.  Virgin  grieving,  by  Nezeo,  Milan. 

62.  Eve  after  the  Fall,  by  Ragani,  Milan. 

And  many  more,  less  notable.     All  of  these  sculptures 
were  in  Italian  marble. 


380  A   POPULAR   TREATISE    ON   GEMS. 

'•  • 

Sfttlactite  and  Stalagmite. 

It  occurs  in  large  tuberous,  undulated  masses,  botryoidal. 
mammillary,  or  concretional,  either  in  icicles  or  circles ; 
has  a  fibrous  fracture  ;  is  translucent ;  of  a  pearly  lustre ; 
color  generally  yellowish-white  and  white  ;  its  composition 
is  calcareous  spar  ;  it  originates  in  caverns,  through  which 
water,  holding  this  in  solution,  filters,  and  on  its  ultimate 
evaporation  leaves  the  carbonate  of  lime  in  various  forms, 
which  sometimes  resemble  altars,  pillars,  animals,  &c. 

Those  pillars  or  icicles  which  are  pendant  from  the  roof, 
and  those  rising  from  the  base,  are  sometimes  divided  into 
stalactite  for  the  former,  stalagmite  for  the  latter.  But  the 
cause  of  their  existence  is  the  same,  and  there  ought  not 
to  be  any  distinction  in  their  name. 

Ornaments  of  stalactite  in  the  shape  of  vases,  &c.,  are 
often  seen  in  fancy  stores.  The  greatest  localities  of  this 
mineral  are,  the  Grotto  of  Antiparos,  and  Bauman's  Cave, 
in  the  Hartz,  which  I  visited  in  1827,  and  which  displays 
gigantic  stalactites;  also  in  Derbyshire.  In  the  United 
States,  are  very  celebrated  caves  which  yield  this  article. 

These  have  been  described  by  my  friend,  Charles  Cra- 
mer, Esq.,  late  Russian  Vice  Consul  at  New  York,  now 
of  the  Isle  of  Wight,  an  enthusiastic  mineralogist,  of  St. 
Petersburg,  in  a  pamphlet  published  by  the  Imperial 
Mineralogical  Society  of  St.  Petersburg,  in  the  German 
language ;  and  as  this  interesting  little  work  is  not  accessi- 
ble to  all,  I  will  here  translate  the  list  of  all  the  caves  enu- 
merate'd  by  him  as  North  American.  We  would  observe 
that  these  are  not  all  situated  in  limestone  regions,  neither 
do  they  all  furnish  stalactites. 

Canada. — Grotto  in  the  Niagara ;  a  cave  in  Lanark, 
Upper  Canada ;  a  smaller  cave  at  the  same  place. 

New  Hampshire. — The  Devil's  cave. 


381 

Vermont. — Caves  in  Bennington ;  caves  in  Dorset. 

Massachusetts. — Natural  bridge  and  cave  at  Nahant ; 
natural  bridge  over  the  Hudsop  brook  ;  cave  near  Sunder- 
land ;  cave  in  Berkshire ;  two  caves  near  New  Marlbo- 
rough ;  cave  near  West  Stockbridge  ;  cave  in  Lanesboro ; 
cave  in  Adams ;  Purgatory,  near  Sutton. 

Connecticut. — West  Rock  cave,  New  Haven. 

Rhode  Island. — Purgatory,  near  Newport ;  Spouting 
cave,  near  Newport.  •  -'4*;  '• 

New  York. — Cave  near  Watertown ;  cave  at  Niagara  ; 
Ball's  cave  ;  Knox's  cave  ;  Monito,  at  Wigwam,  or  Devil's 
Abode ;  Esopus  cave. 

Pennsylvania'.— Devil's  Hole,  in  Bucks  county ;  cave  on 
the  Swatera  river. 

Maryland. — Hughes'  cave ;  cave  at  Harwell. 

Virginia. — Weyer's  cave  ;  Wreast's  cave  ;  Madison's 
cave ;  Zane's  cave ;  Blowing  cave,  near  Panther  Dale ; 
Greenbriar's  cave  ;  cave  on  the  Kanhawa  river  ;  Chapin's 
cave ;  Johnson's  cave  ;  Allen's  cave ;  Ruffner's  cave ;  Roger's 
cave ;  Reid's  cave  ;  Natural  Tunnel  in  Scott  county ;  Natu- 
ral Bridge  in  Rockbridge  county. 

Ohio. — Mason's,  cave  ;  Nature's  Building,  or  Cave  in  the 
Rock. 

Indiana. — Epsom  Salt  cave  ;  cave  near  Corydon. 

Kentucky. — Boone's  cave  ;  Russell's  cave  ;  White  cave ; 
Mammoth  cave ;  cave  on  Crooked  creek. 

Tennessee.— Big-bone  cave  ;  Arched  cave. 

South  Carolina. — Great  Flat  Rock  cave  ;  Lover's  Leap. 

Georgia. — Nicojack  cave. 

Missouri. — Ashley's  cave. 

Mississippi. — Abode  of  the  Great  Spirit  on  the  North 
West  Coast ;  cave  on  Copper  river. 

Mexico. — Dantoe  cave;  Chamacasapa  cave;  San  Felipe 
cave. 


382          A  POPULAR  TREATISE  ON  GEMS. 

Cuba. — Cave  near  Matanzas. 

Hayti. — Cave  near  St.  Domingo. 

Peru. — Cave  in  the  Andes. 

New  Andalusia. — Canipe  cave. 

Mr.  Cramer  mentions  the  size  of  the  stalagmites  in  the 
antechamber  of  Weyer's  cave,  as  being  twelve  feet  high  ; 
those  in  Solomon's  Temple,  of  the  same,  twenty-five  feet 
high,  which  are  nearly  transparent;  and  its  Hermit's  Chan- 
delier, four  feet  high,  and  twelve  feet  in  circumference;  the 
colossal  stalagmite  in  Washington  Hall,  which  is  said  to 
represent  the  Father  of  his  Country  wrapped  in  his  cloak ; 
Pompey's  column,  thirty  feet  high ;  also  Babylon's  Tower, 
thirty  feet  in  circumference. 

Egyptian  Marble. 

This  is  generally  milk-white,  or  grayish-white  and  bluish, 
and  also  black  and  red,  which  is  called  the  rosso  antico;  it 
is  of  a  close  granular  structure,  and  was  a  great  favorite 
with  the  ancient  architects. 

Italian  Marbles. 

"With  these  may  be  counted  the  Parian  marble ;  the  Pen- 
telian  marble ;  the  Venetian  or  Lombardy  marble,  which 
is  quite  translucent ;  the  Luni  and  Carrara  marble  ;  and  the 
Laconian  marble,  or  verd-antique.  They  have  all  yielded 
materials  for  the  most  ancient  Greek  and  Italian  sculptors. 
The  Venus  de  Medici,  the  Diana  Hunting,  and  Venus  leav- 
ing the  Bath,  are  of  Parian  marble ;  a  Bacchus  in  repose,  a 
Jason,  a  Paris,  and  many  Grecian  monuments,  are  from 
Pentelian  marble,  which  comes  from  the  vicinity  of 
Athens. 


MAEBLE.  383 

American  Marble. 
(Additional  from  the  former  edition  of  this  treatise.) 

The  varieties  of  marble,  which  substance  is  inexhaustible 
in  the  United  States,  are  very  numerous ;  and  I  am  proud 
to  assert,' that  for  architectural  and  ornamental  purposes, 
they  will  successfully  compete  with  those  of  any  foreign 
country.  The  colors  are  various,  from  the  snow-white  to 
the  black  with  gold  and  grass-green  veins.  A  small  dis- 
trict in  New  England,  of  about  fifty  miles  in  extent,  con- 
centrates, I  may  say,  the  marbles  which  may  be  collected 
in  Europe  through  a  space  of  two  thousand  square  miles ; 
for  we  find  in  the  county  of  Berkshire,  and  that  of  New 
Haven,  the  representatives  of  marbles  from  Italy  and  Ire- 
land ;  and  the  discoveries  which  are  constantly  being  made 
of  additional  marble  localities  are  a  source  of  great  satis- 
faction. Thirty  years  ago,  the  City  Hall,  of  New  York 
city,  was  built  of  marble  from  West  Stockbridge,  Massa- 
chusetts, which  was  transported  at  great  expense,  a  dis- 
tance of  over  four  hundred  miles ;  whereas,  afterwards,  the 
same  quality  of  marble  was  discovered  on  New  York  island, 
but  a  few  miles  distant.  According  to  Professor  Dewey, 
the  county  of  Berkshire  alone  turned  out  forty  thousand 
dollars'  worth  of  marble  several  years  ago.  I  will  here 
enumerate  a  few  of  the  most  interesting  marbles: 

a.  The  Philadelphia  marble,  which  is  snow  or  grayish 
white,  and  sometimes  variegated  with  blue  veins,  wrhich 
takes  a  very  high  polish. 

Z>.  The  Potomac  marble,  which  is  properly  called  a 
breccia,  being  composed  of  rounded  and  angular  frag- 
ments from  the  size  of  a  pea  to  that  of  an  ostrich's  egg. 
Its  colors  are  red,  white,  gray,  and  blackish-brown,  inter- 
mixed ;  it  takes  a  very  fine  polish,  and  forms  a  most  beau- 
tiful ornamental  stone.  It  comes  from  the  banks  of  the 


384  A  POPULAR  TREATISE  ON  GEMS. 

Potomac,  in  Maryland.  As  specimens  of  this,  we  would 
refer  to  the  .columns  in  the  House  of  Representatives  at 
Washington,  which  are  twenty  feet  high,  and  two  feet  in 
diameter. 

c.  The  Yerd- Antique,  of  New  Haven,  Connecticut.  This 
marble  is  intermixed  with  serpentine  veins,  and  makes  a 
most  beautiful  appearance.     There  are  inexhaustible  quar- 
ries of  it  at  New  Haven  and  Milford ;  it  bids  fair  to  rival 
every  other  ornamental  stone  in  the  world.     Four  chimney- 
pieces  of  this  mineral  were  purchased  for  the  Capitol  at 
Washington;   and   I   lately  examined   a   splendid   centre 
table,  wholly  cut  from  this  marble,  that  was  exhibited  at 
the  tenth  annual  fair  of  the  American  Institute.     It  is  to 
be  hoped  that  some  company  may  undertake  to  introduce 
this  marble  more  extensively  into  notice,  for  it  does  not  yet 
appear  to  be  sufficiently  known  among  our  wealthy  citi- 
zens: the  enterprise  would  be  well  rewarded.     Large  slabs 
may  be  seen  at  the  New  York  Lyceum  of  Natural  History, 
and  in  the  cabinet  of  Yale  College,  New  Haven.     I  possess  a 
very  fine,  large  slab,  polished.     Portsmouth,  Vermont,  like- 
wise furnishes  splendid  verd-antique,  specimens  of  which 
may  be  seen  at  the  American  Institute,  in  New  York. 

d.  Berkshire  county,  in  Massachusetts,  may  justly  be 
called  the  marble  pillar  of  the  United  States ;  and,  as  Pro- 
fessor Hitchcock  remarks,  the  inhabitants  of  that  county 
cannot  but  regard  their  inexhaustible  deposits  of  marble 
as  a  rich  treasure  to  themselves,  and  an  invaluable  legacy 
to  their  posterity.     The  towns,  West  Stockbridge,  Lanes- 
borough,  New  Ashford,  Sheffield,  New  Marlborough,  and 
Adams,  in  that  county,  keep  thousands  of  hands  constantly 
working  in  their  quarries.     In  1827,  two  thousand  seven 
hundred  tons  of  marble  were  exported  from  that  town ;  and 
in  1828,  a  block  of  from  fifty  to  sixty  feet  square,  and  eight 
thick,  was  raised  by  one  charge  of  gunpowder. 


385 

e.  White,  fine,  granular  marble,  bearing  the  closest  re- 
semblahce  to  the  celebrated  Carrara  marble,  is'  obtained 
from  Smithfield,  Rhode  Island ;  Stoneham,  Massachusetts, 
and  near  Hastings,  on  the  Hudson  river. 

Shell  Marble. 

This  mineral  is  a  secondary  marble,  and  is  called  also 
conchitic  marble,  on  account  of  its  containing  petrified 
shells,  which,  when  polished,  conimunicate  to  their  matrix, 
the  marble,  a  most  beautifully  variegated  appearance. 

a.  The  Lumachella  marble  is  a  kind  which  is  very  scarce; 
it  has  a  gray  or  brown  ground,  interspersed  with  shells  of 
a  circular  form  and  golden  color,  and  when  held  towards 
the  reflection  of  light,  displays  red,  blue,  and  green  tints, 
like  those  of  the  precious  opal  or  iridescent  labrador.' 

It  is  sometimes  seen  in  the  form  of  pins  and  other  jewelry, 
but  stands,,  on  account  of  its  scarcity,  very  high  in  price ; 
the  only  locality  is  in  Carinthia ; .  one  formerly  in  Devon- 
shire, England,  being  exhausted.  Some  splendid  specimens 
from  Carinthia,  are  in  the  collection  of  Baron  de  Lederer, 
Austrian  consul  for  this  city ;  and  a  very  fine  specimen  of 
the  lumachella,  at  the  Boston  Society  of  Natural  History, 
was  marked  with  the  locality  of  Neufchatel. 

b.  Panno   di  morto,  or  funeral  pall,  is  a  deep  black 
marble,  with  white  shells,  like  snails;  it  is  only  seen  at 
Rome,  and  is  very  scarce. 

c.  Bristol  marble,  from  England,  is  a  black  marble,  inter- 
spersed with  white  shells. 

d.  Italian  shell  marbles  from  Florence,  Lucca,  and  Pisa, 
are  red,  containing  white  shells  (ammonites). 

e.  French  shell  marbles  are  very  numerous ;  those  from 
Narbonne  are  black  with  white  belemnites ;  that  from 
Caen  is  a  brown  marble  with  madreporites  j  and  those  from 

17 


386  A   POPULAR  .TREATISE   ON   GEMS. 

Languedoc  are  of  a  fiery  red  color,  mixed  with  white  and 
gray  univalve  shells ;  of  this  Napoleon's  eight  columns  for 
his  triumphal  arch  in  the  CarouselJ  at  Paris,  were  cut. 

f.  The  United  States  "have  a  great  many  shell-marble 
quarries  ;  but  they  are  all  black  and  gray.  Those  of  Tren- 
ton Falls,  Little  Falls ;  near  Seneca  lake ;  Northumber- 
land county,  Pennsylvania;  Bernardston,  Massachusetts, 
and  Hudson,  New  York,  contain  either  trilobitea  or  encri- 
nites ;  some  take  a  very  fine  polish. 

PISOLITE   AND    OOLITE. 

These  minerals  are  likewise  composed  of  carbonate  of 
lime;  they  occur  massive,  and  in  distinct  concretional 
layers,  either  in  the  form  of  peas  or  other  round  grains  or 
pebbles,  and  are  of  white,  yellowish-white,  brownish,  or 
reddish  color ;  when  cut  and  polished,  they  make  a  fine 
ornamental  stone,  and  present  a  very  effective  appearance. 
The  former  is  found  in  alluvial  deposits  of  the  hot  water 
mineral  springs  of  Carlsbad,  in  Bohemia,  and  the  baths  of 
St.  Philip,  in  Tuscany  ;  the  latter  forms  large  beds  in  Eng- 
land and  France.  The  city  of  Bath,  in  England,  is  mostly 
built  of  this  limestone. 


ROCK   OF    GIBRALTAR. 

This  is  likewise  a  carbonate  of  lime ;  occurs  massive, 
mostly  striped ;  is  yellowish-white,  yellow,  and  brownish ; 
is  only  found  in  that  rock  from  whence  it  takes  its  name, 
and  has  been  heretofore  a  great  favorite  for  jewelry  and 
other  ornaments.  At  this  day  we  see  in  shops  and  private 
houses,  pins,  brooches,  ear-rings,  seals,  cane-heads,  snuff- 
boxes, letter-holders,  vases,  urns,  candelabras,  obelisks,  &c.3 
formed  of  it.  It  takes  a  high  polish. 


APATITE.  387 


APATITE. 

This  mineral  was  named  by  Werner,  on  account  of  its 
color  being  so  deceptive  (anaraa),  to  deceive),  as  it  resembles 
the  color  of  some  -other  precious  stones ;  it  occurs  in  six- 
sided  prisms,  massive  and  globular ;  has  a  conchoidal  frac- 
ture ;  a  vitreous  lustre ;  color  usually  sea-green,  bluish-green, 
or  violet-blue,  sometimes  white,  occasionally  yellow,  gray, 
and  red ;  is  transparent  and  opaque ;  it  resembles  the  beryl 
and  emerald,  but  is  distinguishable  by  color  and  hardness ; 
hardness,  4'5  to  5 ;  specific  gravity,  3  to  3'235.  A  bluish 
opalescence  is  observed  in  the  direction  of  the  vertical  axis 
in  some  specimens,  especially  in  the  white  variety;  fracture 
conchoidal  and  uneven ;  brittle.  Some  varieties  are  phos- 
phorescent when  heated,  others  become  electric  by  friction. 
It  is  infusible  alone  before  the  blowpipe,  except  at  the 
edges;  dissolves  slowly  in  nitric  acid,  and  without  effer- 
vescence. 

Apatite  usually  occurs  in  primitive  rocks ;  is  often  found 
in  veins  of  primitive  limestone  traversing  granite, — it  also 
occurs  in  serpentine  and  in  ancient  volcanic  rocks. 

It  contains  about  ninety  per  cent,  subsesquiphosphate  of 
lime,  and  the  rest  is  chloride  and  fluoride  of  calcium.  On 
account  of  its  phosphoric  acid,  the  compact  varieties  of 
apatite  have  become  an  important  article  of  trade  for  agri- 
cultural purposes. 

The  principal  localities  are  in  Saxony,  at  Ehrenfriders- 
dorff,  in  the  Hartz  mountains,  where  the  author  collected, 
in  his  youthful  years,  some  magnificent  crystals;  also  in 
Bohemia,  at  Schlackenwald ;  in  Cumberland  arid  Devon- 
shire, England;  at  §t.  Gothard,  in  Switzerland;  and  a 
greenish-blue  variety,  called  moroxite,  is  found  in  Norway, 
at  Arendal. 

Asparagus  stone,  which  is  of  a  yellow  color  and  trans- 


388  A  POPULAR  TREATISE   ON   GEMS. 

lucent,  is  found  at  Estremadura,  in  Spain,  of  which  many 
fine  specimens  may  be  seen  at  the  Academy  of  Natural 
Sciences  of  Philadelphia, — in  Maclure's  collection ;  also  in 
Zillerthal,  Tyrol,  where  it  is  imbedded  in  talc.  The  phos- 
phorite, or  massive  varieties,  from  Spain  and  Bohemia,  has 
been  found  in  large  beds.  In  the  United  States  it  occurs 
in  a  vein  of  limestone  intersecting  the  granite  at  Gouver- 
neur,  St.  Lawrence  county,  New  York,  and  crystals  of 
ten  to  twelve  inches  long  and  one  and  a  half  to  two  inches 
in  diameter,  of  fine  sea-green  color,  were  formerly  found 
in  abundance. 

Yale  College  has  some  fine  specimens  of  this  crystallized 
variety,  from  Baron  Lederer's  cabinet.  Professor  Shep- 
herd, Mr.  Francis  Algar,  and  Dr.  Charles  T.  Jackson,  in 
Boston,  possess  many  fine  and  large  crystals.  Mr.  Kranz, 
in  Bonn,  was  fortunate  to  procure,  through  his  collector, 
some  gigantic  crystals  of  this  beautiful  mineral.  There  are  • 
some  other  localities  of  the  crystallized  variety  in  the 
United  States,  such  as  Amity,  New  York,  where  it  occurs 
of  a  green  color  in  white  limestone,  presenting  the  primary 
form,  and  accompanied  with  pyroxene  and  scapolite.  Crys- 
tallized and  massive  specimens  of  a  bluish-green  color 
occur  at  Boston,  Massachusetts,  associated  with  sphene  and 
petalite.  Reddish-brown  crystals,-  of  one  inch  in  length, 
have  been  obtained  from  a  granite  vein  in  Greenfield,  New 
York.  The  massive  variety  of  phosphate  of  lime  from 
Crown  Point,  New  York,  has  furnished  several  thousand 
tons  for  export  to  England  as  a  fertilizing  agent,  and  the 
concretional  variety  of  phosphate  of  lime  from  Dover  and 
Franklin,  in  New  Jersey,  has  likewise  yielded  considerable 
quantities  for  a  manure.  These  two  latter  varieties  have 
been  treated  with  sulphuric  acid  (oil  oT  vitriol),  in  order  to 
obtain  a  superphosphate  of  lime,  which  is  now  considered 
the  most  useful  vehicle  to  enrich  the  soil,  and  to  produce 


MICA.  389 

the  most  prolific  crops.  Liebig  and  Johnstone,  the  two 
great  agricultural  chemists,  have  demonstrated  beyond  any 
controversy  that  .the  resuscitation  of  worn-out  soils  depends 
materially  upon  the  addition  of  phosphate  of  lime ;  and 
hence  the  application  of  bone-dust,  which  is  a  phosphate  of 
lime,  and  guano,  which  contains  the  latter  ingredient  with 
the  ammoniacal  salts  in  combination,  of  which  at  the 
present  day  100,000  tons  are  annually  consumed  by  the 
farmer,  along  with  the  artificially  prepared  superphosphate 
of  lime,  are  well  known,  but  do  not  belong  here. 

LEPIDOLITE. 

This  mineral  derives  its  name  from  the  Greek  language, 
from  its  scaly  structure ;  it  occurs  massive,  presenting  an 
aggregate  of  minute,  shining,  flexible  scales  or  hexagonal 
plates  ;  it  has  a  splintery  fracture  ;  a  glistening  and  pearly 
lustre;  is  translucent  on  the  edges;  its  colors  are  lilac, 
rose-red,  pearl-gray,  greenish-yellow,  and  blue ;  it  is 
scratched  by  glass,  and  yields  to  the  knife ;  has  a  specific 
gravity  of  2'81  ;  is  fusible  with  ease  into  a  transparent 
globule.  It  is  found  in  granite  and  primitive  lime,  in 
Monrovia,  France,  island  of  Elba,  Corsica,  Sweden,  and  in 
the  United  States,  in  Maine,  New  Hampshire,  Vermont, 
and  Massachusetts.  It  is  cut  in  Europe  for  various  orna- 
ments, such  as  plates,  vases,  snuif-boxes,  &c.,  and  will,  'I 
trust,  at  some  future  day,  be  more  extensively  used  in 
jewelry ;  for  there  are  some  variegated  specimens  of  a 
peach-blossom  color,  and  very  fine  granular  structure, 
which  are  extremely  beautiful. 

MICA. 

This  mineral  occurs  crystallized,  in  six-sided  tables  and 
oblique  rhombic  prisms,  and  massive ;  also,  disseminated ; 


390          A  POPULAR  TREATISE  ON  GEMS. 

it  has  a  perfectly  foliated  structure ;  a  glittering  and 
metallic  lustre ;  is  transparent  and  translucent ;  very  fusi- 
ble and  elastic ;  its  colors  are  white,  green,  black,  brown, 
peach-red,  yellowish,  and  bluish ;.  it  has  a  specific  gravity 
of  2'7.  It  is  found  in  primitive  rocks,  and  forms  an  ingre- 
dient in  granite,  gneiss,  mica  slate,  and  other  rocks,  where 
it  more  or  less  predominates ;  its  localities  are,  therefore, 
universal,  but  in  Siberia  it  forms  large  beds,  and  is  quarried 
for  special  purposes,  such  as  a  substitute  for  glass  windows ; 
and  although  the  United  States  afford  ample  localities  of 
it,  yet  a  few  years  ago  quantities  were  imported  here  for 
the  doors  of  Nott's  stoves. 

The  plumose  mica  is  a  beautiful  variety,  and  derives  its 
name  from  its  resemblance  to  a  quill  or  plume,  the  lamellar 
or  fine  delicate  crystals  diverging  in  such  a  manner  as  to 
present  this  appearance.  It  is  of  a  pearl-gray  color.  It  is 
found  in  the  United  States,  at  Williamsbury,  Mass.,  Hart- 
ford, Conn.,,  and  many  other  places.  The  green  mica  is  of 
a  beautiful  grass-green  color,  and  is  found  in  Brunswick, 
Maine.  The  rose-red  mica  is  a  very  beautiful  mineral,  and 
is  found  in  numerous  places,  in  this  country ;  principally  at 
Goshen,  Chesterfield,  Mass.;  Acworth,  N.  H. ;  Bellows 
Falls,  Vt.,  &c.  Mica  may,  when  of  good  colors,  be  used 
for  jewelry  and  other  ornaments,  as  well  as  the  lepidolite. 


PYRITES. 

This  mineral  is  called  sulphuret  of  iron,  iron  pyrites,  and 
markasite.  It  occurs  crystallized  in  many  forms ;  such  as 
the  cube,  octahedron,  and  dodecahedron  ;  also  massive, 
disseminated,  capillary,  and  cellular;  it  has  a  conchoidal 
fracture ;  a  brilliant  metallic  lustre ;  its  colors  are  bronze, 
yellow,  brass-yellow,  and  steel-gray.  This  mineral  takes  a 
very  high  polish,  and  from  its  fine  lustre  looks  extremely 


PORPHYRY.  391 

well  when  cut  in  the  form  of  a  brilliant  or  rose.  It  was 
formerly  much -used  in  jewelry  for  ear-rings,  rings,  pins, 
and  necklaces.  It  was,  in  former  times,  considered  a  great 
preservative  of  health.  It  is  now  but  seldom  seen,  except 
in  mineralogical  cabinets. 

ROSE   MANGANESE. 

This  mineral  is  called  in  mineralogical  works  the  silicious 
oxide  of  manganese,  and  also  the  carbonate  of  manganese. 
It  occurs  massive;  has  a  foliated  structure;  a  conchoidal 
fracture ;  a  shining  lustre ;  it  scratches  glass ;  its  colors  are 
rose-red,  reddish,  and  yellowish. 

It  is  found  in  Siberia,  Sweden,  Hungary,  England ;  and 
in  the  United  States,  at  Middlebury,  Vt.,  and  at  Cumming- 
ton  and  Plainfield,  Mass.,  where,  according  to  Professor 
Hitchcock,  the  silicious  oxide,  or  according  to  Dr.  Thomp- 
son, the  bisilicate  of  manganese  is  found  in  great  abundance. 
Since  it  takes  a  very  high  polish,  and  is  much  wrought  at 
Ekaterinenburg,  in  Siberia,  into  many  ornaments,  it  is  con- 
fidently to  be  hoped  that  it  may  also  find  its  amateurs  in 
this  country,  as  it  is  very  easy  to  cut  and  polish,  and  the 
material  is  so  plenty. 

PORPHYRY. 

This  mineral  forms  rocks  in  a  geological  sense,  but  is 
properly  a  compact  felspar.  It  has  various'  colors  and 
shades,  and  contains  imbedded  crystals  of  felspar  and 
quartz.  The  name  porphyry  signifies  purple,  from  iroptyvpa, 
such  having  been  the  usual  color  of  the  ancient  porphyries ; 
the  same  rock  exhibits,  however,  almost  every  variety  of 
color ;  it  is  the  hardest  of  all  rocks,  and  when  polished,  Is 
probably  the  most  enduring.  It  is  much  used  in  Europe 
for  ornamental  and  architectural  purposes ;  also  for  slabs, 
mortars,  and  other  articles. 


392  A  POPULAR  TREATISE  ON  GEMS. 

In  the  United  States,  porphyry  has  never  been  used  for 
any  purpose ;  but  Professor  Hitchcock  f  emarks,  in  his 
Geological  Report  of  the  State  of  Massachusetts,  that  it 
would  be  strange  if  an  increase  of  wealth  and  refinement 
should  not  create  some  demand  for  so  elegant  and  enduring 
a  rock  as  porphyry.  In  the  same  excellent  work  the  author 
divides  porphyry  into  four  varieties,  as  occurring  in  Massa- 
chusetts, in  the  neighborhood  of  Boston : 

1st.  Compact  felspar,  with  several  predominating  colors; 
the  one  with  yellow,  resembling  the  Turkey  stone;  one 
with  red,  from  brownish  to  blood-red,  closely  resembling 
jasper ;  one  with  a  rose-red  color,  resembling  the  rose  petro- 
silex  of  Europe. 

2d.  Antique  porphyry ;  closely  resembling  that  European 
porphyry  which  was  employed  by  the  ancients  in  monu- 
ments and  ornamental  furniture  and  forms,  and  is,  when 
polished,  a  beautiful  ornament.  It  presents  numerous  vari- 
eties and  shades  of  color :  one  of  the  most  elegant  is  the 
light-green ;  then  a  deep-green ;  red  of  various  shades ; 
reddish-brown ;  black,  or  nearly  so  ;  gray,  and  purple ;  and 
the  imbedded  crystals  are  usually  of  a  light  color,  some- 
times white,  brown,  and  greenish. 

3d.  Porphyry  with  two  or  more  minerals  imbedded,  and 
having  a  base  of  common  felspar.  This  mineral  is  between 
sienite  and  porphyry,  resembling  the  trachytic  porphyry, 
and  is  generally  unfit  for  ornamental  purposes ;  the  quartz 
which  it  contains  is  hyaline  and  smoky. 

4th.  The  brecciated  porphyry,  which  is  composed  of  an- 
gular fragments  of  porphyry  and  compact  felspar,  reunited 
by  a  paste  of  the  same  material ;  the  fragments  are  also  of 
various  colors,  usually,  however,  gray  and  red ;  the  rock  is 
very  hard,  and  when  polished,  furnishes  specimens  of  great 
delicacy  for  ornamental  purposes. 

Porphyry  is  much  used  in  England  for  paving  stones,  in 


SEENITE.  393 

the  entrance  halls  of  large  public  buildings  or  private 
mansions,  and  the  Cornwall  porphyry  is  particularly  cele- 
brated-for  its  various  tints  of  colors.  The  author  distinctly 
recollects  four  slabs :  one  was  a  black  slab ;  another,  red ; 
a  third,  green;  and  a  fourth,  a  large  slab,  containing 
twenty-four  specimens  of  various  variegated  rocks  of  por- 
phyry. Also,  the  elvan-stone,  from  the  quarries  of  New 
Quay,  in  Cornwall,  which  is  a  beautiful  porphyry.  The 
large  slab,  weighing  about  eight  hundred  pounds,  was  of 
very  fine  red  color ;  it  was  without  flaw  or  defect. 

In  Prussia  porphyry  is  abundant,  and  there  were  some 
fine  specimens  in  the  London  Exhibition,  such-  as  a  table,  a 
small  column  and  tazza ;  the  latter  was  a  round  slab  of  red 
color  and  fine  texture,  and  the  tazza  vase  and  pedestal  were 
of  the  same  material. 

From  Sweden  and  Norway  a  sienitic  porphyry,  of  gray- 
ish-red color,  was  also  in  the  London  Exhibition. 

The  porphyry  vase  in  the  Berlin  Museum,  which,  accord- 
ing to  the  author's  recollection,  is  about  eight  feet  high 
and  six  feet  in  diameter,  is  well  deserving  a  place  hi  this 
treatise,  as  it  is  unique  of  its  kind  in  the  world. 


SIEXITE. 

This  rock  is  composed  essentially  of  felspar  and  horn- 
blende, and  sometimes  contains  quartz  or  mica,  or  both. 
When  polished,  it  forms  the  most  splendid  ornamental 
stone  of  all  rocks ;  it  is  very  hard  ;  and  its  color  and  the 
mode  of  distribution  of  the  various  ingredients,'  make  it 
very  agreeable  to  the  eye.  It  much  resembles  granite,  and 
is  often  almost  identical  with  it ;  but  by  close  inspection  it 
may  be  distinguished  from  the  want  or  addition  of  the 
component  ingredients. 

Professor  Hitchcock  describes  six  varieties  of  sienite: 


394  A  POPULAR  TREATISE  ON  GEMS. 

1st.  That  sienite  which  is  composed  of  felspar  and  horn- 
blende, when  the  first  is  white,  greenish,  and  yellowish,  and 
the  latter  inyariably  black. 

2d.  Felspar,  quartz,  and  hornblende ;  the  first  is  foliated, 
and  commonly  of  grayish,  bluish,  or  yellowish  color ;  the 
second  from  quite  light  to  dark  color  and  hyaline ;  and  the 
latter  is  black.  Under  this  variety  the  quarries  at  Quincy 
and  Cape  Ann  have  been  arranged  by  the  author  (which 
are  generally  called  granite),  on  account  of  the  absence  of 
mica.  The  •  Quincy  granite,  or  rather  sienite,  is  that  cele- 
brated architectural  material  used  in  the  cities  of  Boston 
and  New  York,  for  those  huge  and  magnificent  edifices, 
public  as  w^ell  as  private,  erected  within  the  last  six  years ; 
and  it  may  be  supposed  that  five  thousand  buildings  in  the 
city  of  New  York  have  been  constructed  with  this  splendid 
article. 

3d.  Felspar,  hornblende,  quartz,  and  mica.  This  rock, 
likewise,  has  a  beautiful  appearance,  but  is,  as  yet,  less 
wrought  than  the  other  varieties.  The  felspar  and  horn- 
blende are  predominant.  The  quartz  is  in  small  grains,  and 
the  mica  is  black, 

4th.  Porphyritic  sienite ;  its  base  is  quartz  and  felspar, 
and  the  hornblende  is  almost  entirely  absent ;  it  has  a 
porphyritic  aspect ;  the  felspar  predominates.  It  is  the 
most  ornamental  stone  when  polished. 

5th.  Conglomerated  sienite;  it  is  a  quarternary  com- 
pound of  felspar,  hornblende,  quartz,  and  mica,  but  all  in 
rounded  or  conglomerated  masses,  having  the  aspect  of  a 
pudding-s'tone ;  the  nodules  are  from  half  an  inch  to  six 
inches  in  size,  and  may  be  easily  broken  out  of  the  mass, 
and  the  hornblende  predominates  mostly  in  them.  It  is 
unfit  for  architectural  purposes. 

6th.  Augite  sienite ;  in  this  rock  the  hornblende  ia 
present  and  rnica  absent.  It  is  composed  of  black  horn- 


SIEXTTE.  395 

blende,  greenish  augite,  and  yellowish  felspar ;  all,  except 
the  felspar,  presenting  a  crystalline  structure;  it  is  also 
composed  only  of  augite  and  felspar. 

The  name  of  the  rock  sienite  was  originally  derived  from 
Syene,  in  Upper  Egypt,  from  whence  the  first  specimen 
was  procured ;  it  was  examined  and  identified  by  Werner ; 
many  of  the  Egyptian  monuments,  such  as  Cleopatra's 
Needle,  and  Pompey's  Pillar,  were  obtained  from  there. 

There  are  valuable  quarries  of  sienite  in  abundance  in 
the  State  of  New  York.  It  is  a  durable  and  beautiful 
stone,  and  may  be  quarried  in  large' blocks,  but  on  account 
of  its  great  hardness  requires  much  labor  to  dress  it. 

Along  the  North  River  there  are  many  localities :  An- 
thony's Nose,  or  Anthony  s  Face,  which  is  a  mountain  in 
the  northwest  corner  of  Putnam  county,  opposite  Fort 
Montgomery.  It  is  called  so  in  consequence  of  the  profile 
bearing  a  rude  resemblance  to  the  human  face,  that  may 
be  seen  in  one  position,  when  passing  it ;  but  on  account  of 
its  steepness,  being  five  hundred  feet  in  height,  it  is  more 
generally  called  Breakneck  Mountain.  Here  is  the  granitic 
sienite.  It  is  composed  of  a  darkish-gray  colored  felspar, 
with  a  little  black  hornblende. 

In  Peekskill  bay,  on  the  Hudson  river,  and  the  adjoining 
hills  for  five  miles  in  length,  very  valuable  quarries  of  this 
fine  rock  may  be  quarried. 

The  sienite  rock  of  the  Highlands  is  veTy  extensive ; 
such  as  the  Target  rock  on  Constitution  Island,  opposite 
West  Point,  and  all  along  the  slopes  of  the  mountains  in 
the  Highlands,  there  are  boulders  and  blocks  of  this  valu- 
able and  useful  rock. 

Fort  Putnam,  near  West  Point,  and  the  base  of  Butter 
Hill,  four  miles  north  of  West  Point,  are  composed  of  sienite. 

When  it  was  ascertained  that  the  famous  rock  from 
Syene,  in  Upper  Egypt  (so  much  employed  in  ancient 


396  A  POPULAR  TREATISE  ON  GEMS. 

monuments),  and  from  which  the  name  of  sienite  was  de- 
rived, was  nothing  but  granite  with  black  mica,  and  also, 
that  Mount  Sinai,  in  Arabia,  was  composed  of  genuine 
sienite,  a  French  geologist  proposed  to  substitute  sinaite 
for  sienite,  but  the  name,  although  a  good  one,  has  never 
been  adopted. 

The  Quin cy  and  Cape  Ann  sienite,  which  is  sent  from 
Massachusetts  to  all  parts  of  the  United  States,  and  forms 
such  a  beautiful  architectural  material,  is  composed  of 
felspar,  quartz,  and  hornblende. 

GRANITE. 

This  rock  is  composed  of  quartz,  felspar,  and  mica,  and 
forms  the  crust  of  our  globe.  It  occurs  over  the  whole 
earth,  and  the  eastern  part  of  the  United  States  is  abund- 
antly furnished  with  this  valuable  mineral.  As  a  building 
material  it  has  been  most  extensively  used  for  the  last  ten 
years ;  but  the  great  fire  in  New  York,  which,  in  Decem- 
ber, 1835,  consumed  seven  hundred  buildings,  among 
which  about  two  hundred  were  of  granite,  has  given  a 
sufficient  proof  that  granite  is>  in  this  changeable  climate, 
unfit  for  a  building  material,  but  that  it  may  be  usefully 
employed  for  ornamental  and  architectural  purposes,  where 
it  is  not  constantly  exposed  to  the  atmosphere  and  weather, 
which  make  it  so  liable  to  decomposition. 

Nevertheless,  granite  continues  to  be  generally  employed 
in  the  erection  of  public  buildings,  warehouses,  bridges, 
&c.,  and  begins  to  form  an  important  pecuniary  object  to 
the  merchant  and  mechanic ;  and  on  this  account  I  cannot 
forbear  to. treat  more  fully  on  its  general  characters,  and  I 
must  confess  that  the  rich  granite  treasures  of  Connecticut, 
Rhode  Island,  and  Massachusetts,  which  I  had  occasion  to 
examine  a  short  time  since,  on  a  journey  into  those  regions, 


GEANTTE.  397 

deserve  fully  all  the  encomiums  bestowed  upon  them  in 
Hitchcock's  Report  on  the  Geology  of  Massachusetts,  and 
in  Shepherd's  Report  on  the  Geological  Survey  of  Connec- 
ticut. So  abundant  and  large  are  the  granite  rocks  in  the 
eastern  part  of  the  United  States,*  that  some  single  locali- 
ties are  sufficient  to  supply  many  countries  with  this  lucra- 
tive article. 

Professor  Hitchcock  divides  the  granite  of  Massachusetts 
into  four  varieties,  viz : 

1.  Common  granite,  which,  according  to  him,  embraces 
nine  tenths  of  the  granite  in  Massachusetts :  the  ingre- 
dients are  a  distinct  crystalline  structure,  of  mixed  and  dis- 
criminating colors. 

2.  Pseudomorphous  granite  is  that  variety  in  which  the 
mica  separates  distinctly  the  other  ingredients,  which  are 
closely  mixed. 

•  3.  Porphyritic  granite  :  it  contains,  besides  the  usual 
composition  of  quartz,  felspar,  and  mica,  distinct  imbedded 
crystals  of  felspar. 

4.  Graphic  granite :  this  variety  consists  of  quartz  and 
felspar  only ;  the  cross-fracture  presents  the  appearance  of 
written  characters. 

Professor  Shepherd  divides  the  ornamental  granite  of  the 
State  of  Connecticut  into  eight  different  types,  viz. : 

1.  Gray  granite. 

2.  White  granite.     This  variety  I  have  examined  myself 
in  Plymouth,  Connecticut,  and  so  beautiful  was  its  color 
and  close  granular  texture,  that  I  took  it  at  a  distance  for 
a  sandstone,  or  white  marble. 

3.  Flesh-colored  granite. 

4.  Red  granite. 


*  Professor  Hitchcock  remarks  that  there  is  not  a  town  in  Massachusetts 
in  which  more  or  less  granite  does  not  occur,  eiiher  as  situ  or  as  boulders. 


398  A   POPULAR   TREATISE   ON   GEMS. 

5.  Epidotic  granite. 

6.  Porpbyritic  granite. 

7.  Chloritic  granite. 

8.  Sienitic  granite. 

In  Rhode  Island  a  fine  white  granite  has,  according  to 
Dr.  Webb,  of  Providence,  been  employed  fgr  the  erection 
of  the  arcade  of  that  city,  from  a  quarry  in  Johnstone,  five 
miles  from  Providence. 

The  manner  in  which  granite  is  usually  split  out  at  the 
quarries,  is  this :  a  number  of  holes,  of  a  quadrangular 
form,  a  little  more  than  an  inch  wide  and  two  or  three 
inches  deep,  are  drilled  into  the  rock  at  intervals  of  a  few 
inches,  in  the  direction  in  which  it  is  wished  to  separate 
the  mass.  Iron  wedges,  having  cases  of  sheet  iron,  are 
then  driven,  at  the  same  time  and  with  equal  force,  into 
these  cavities ;  and  so  prodigious  is  the  power  thus  exerted, 
that  masses  of  ten,  twenty,  thirty,  and  even  fifty  and  sixty 
feet  long,  and  sometimes  half  as  many  wide,  are  separated. 
These  may  be  subdivided  in  any  direction  desired  ;  and  it 
is  common  to  see  masses  thus  split  till  their  sides  are  less 
than  a  foot  wide,  and  their  length  from  ten  to  twenty  feet. 

The  price  of  the  granite  from  these  quarries,  according 
to  Professor  Hitchcock,  is  from  forty  to  forty-five  cents  per 
superficial  foot,  and  for  hammering  and  fine  dressing  it, 
about  thirty  cents  the  superficial  foot,  such  as  in  the  style 
of  the  Tremont  House  in  Boston  ;  common  work  from 
twenty  to  thirty-five  cents  ;  posts  for  stone  fronts  cost 
thirty-four  cents  per  foot.  The  enterprising  citizens  of  the 
city  of  New  York  have  erected  gigantic  monuments  of 
granite,  for  future  generations  to  admire. 

New  York  abounds  in  granite,  both  east  and  west  of  the 
Hudson  river,  Staten  Island,  Westchester  and  Putnam 
counties.  In  the  city  of  New  York,  a  large  bed  of  fine 
granite  extends  froin.  Thirty-first  street  on  the  west  side, 


GRANITE.  399 

and  from  Twenty-fourth  street  in  the  middle,  to  Sixtieth 
street  on  the  north.  The  Croton  Aqueduct  is  mostly 
built  of  granite  quarried  in  Tenth  avenue  near  Forty-eighth 
street. 

Granite  abounds  in  Rockland  and  Orange  counties ;  it 
occurs  in  beds,  veins,  and  irregular  masses,  forming  hills, 
and  often  the  tops  of  mountains. 

The  fine-grained  varieties  of  granite  are  best  for  eco- 
nomical uses.  When  granite  contains  distinct  crystals  of 
felspar,  it  is  called  porphyritic ;  when  the  ingredients  are 
blended  into  a  finely  granular  mass,  with  imbedded  crys- 
tals of  quartz  and  mica,  it  is  called  by  French  writers, 
eurite.  A  granular  mixture  of  quartz  and  felspar  is  called 
pegmatite. 

In  England,  Cornwall  is  particularly  celebrated  for  its 
granite ;  the  obelisk  from  the  Lamorran  quarries,  twenty- 
two  feet  high,  which  was  exhibited  at  the  London  Exhi- 
bition, was  twenty-one  tons  in  weight,  and  of  a  coarse 
grain,  and  another,  from  Cornseco  granite,  weighing  thirty- 
one  tons,  and"  eighteen  feet  high,  were  beautiful  specimens 
of  this  useful  rock.  They  were  each  wrought  from  a  single 
block  of  granite,  and  were  remarkable  for  extreme  fineness 
and  closeness  of  grain,  and  the  delicacy  of  finish  which  was 
thereby  obtained. 

The  granite  column  of  Cheesewing  granite,  the  property 
of  the  Prince  of  Wales,  near  Liskeard,  in  Cornwall,  was 
likewise  a  magnificent  piece.  It  was  thirty  feet  high. 

The  bust  and  pedestal  of  blue  Peterhead  granite  was 
also  an  interesting  specimen  of  its  kind. 

Swedish  granite  has  been  known  for  many  centuries ;  it 
is  obtained  from  extensive  quarries  on  the  island  of  Ma- 
leuva,  on  the  west  coast  of  Sweden.  It  bears  a  high  polish 


400         .  A  POPULAR  TREATISE  ON  GEMS. 


PEARLS. 

Pearls  are  concretions,  consisting  of  carbonate  of  lime, 
having  a  roundish,  tubercular,  or  angular  form ;  a  white, 
gray,  blue,  or  green  color ;  a  shining  lustre,  and  the  hard- 
ness of  lime;  specific  gravity,  2*68.  They  are  found  in 
several  bivalve  shells — the  meleagrina  margaritifera,  haliotis 
gigas,  and  haliotis  iris,  and  a  large  species  of  turbo,  which 
shells  are  known  in  commerce  as  flat  shells,  ear  shells,  green 
snail  shells,  buffalo  shells,  and  Bombay  shells  ;  many  unios, 
alaniadontas,  &c.  Mother  of  pearl  is  the  internal  or  nacre- 
ous layer  of  such  shells.  These  precious  substances  are  the 
result  of  an  excretion  in  superimposed  concentric  laminae  of 
a  peculiarly  fine  and  dense  nacreous  substance,  which  con- 
sists of  membrane  and  carbonate  of  lime.  The  finest  qual- 
ity is  produced  by  the  bivalve  of  the  Indian  seas,  called  par 
excellence  the  pearl  oyster  (meleagrina  margaritifera}.  In 
the  United  States  the  alasmadonta  arcuata,  corresponding 
with  the  mytilus  margaritiferus  of  Barnes,  the  unio  ochra- 
ceus,  unio  complanatus,  and  many  other  species,  contain 
the  pearls,  and  according  to  the  nacre  of  the  shells  the 
color  of  the  pearl  is  corresponding. 

The  origin  of  pearls  is  by  some  considered  to  be  unfructi- 
fied  eggs ;  by  others,  a  morbid  concretion  or  calculus, 
produced  by  the  endeavor  of  the  animal  in  the  shell  to  fill 
up  holes  therein ;  by  others  again,  as  mere  concretions  of 
the  juice  of  which  the  shell  has  been  formed,  and  with 
which  the  animal  annually  augments  it.  It  is  very  plausi- 
ble, however,  that  the  animal  of  the  shell  is  attacked  often 
by  enemies,  such  as  the  boring  shells  (turritella),  &c. ;  that 
grains  of  sand,  or  any  other  pointed  substance,  which,  on 
such  occasions,  come  within  the  shell,  stick  fast  and  aug- 
ment with  the  growth  of. the  shell;  it  is  also  known  that 
pearls  may  be  produced  artificially,  by  pressing  a  sharp 


PEARLS.  401 

body  on,  or  by  boring  a  hole  in,  the  shell.  The  Chinese 
are  in  the  habit  of  laying  a  string  with  five  or  six  small 
pearls  separated  by  knots,  inside  of  the  shells,  when  the  fish 
are  exposing  themselves  to  the  sun,  and  taking  them  out 
after  some  years,  whereby  they  obtain  very  fine  and  large 
pearls,  and  but  a  little  open  on  the  side  where  they  were 
adherent  to  the  shell.  The  pearl  fishers  say  that  when  the 
shell  is  smooth  and  perfect,  they  never  expect  to  find  any 
pearls,  but  always  do  so  when  it  has  begun  to  be  deformed 
and  distorted.  It  was  therefore  concluded,  that  as  the  fish 
grew  old,  the  vessels  containing  the  juice  for  forming  the 
shell  and  keeping  it  in  vigor,  became  weak  and  ruptured, 
and  from  this  juice  accumulating  in  the  fish,  the  pearl  was 
formed,  and  the  shell  brought  to  decay,  as  supposed  by  M. 
Reaumur.  It  would  be,  according  to  this  idea,  a  sure 
guide  to  know  from  the  form  of  the  shell,  whether  the 
pearl  is  large  or  small;  and  thus  by  the  smaller  ones  being 
thrown  back  into  the  sea,  a  constant  crop  of  large  pearls 
might  be  obtained.  The  mother-of-pearl  fish  is  found  in 
the  East  and  West  Indies,  and  other  seas  in  warm  latitudes, 
and  in  the  rivers  of  north  and  middle  Europe.  In  some 
parts  of  the  globe,  they  are  found  in  clusters,  containing  a 
great  number;  the  places  where  found  are  caUed  pearl- 
banks.  The  most  famous  are  near  the  coast  of  Ceylon, 
that  of  Japan,  and  in  the  Persian  Gulf,  near  the  island  of 
Bahreim ;  also  near  the  coast  of  Java,  Sumatra,  &c.  The 
finest  and  most  costly  pearls  are  called  the  Oriental,  and 
are  from  the  above  places ;  they  are  all  white  or  yellowish ; 
those  from,  the  Persian  Gulf,  on  account  of  their  perfect 
whiteness,  are  preferred  to  those  from  Ceylon.  Pearls  are 
collected  in  rivers  with  the  hand,  but  in  seas  it  is  the  busi- 
ness of  divers,  brought  up  to  this  most  dangerous  occupa- 
tion from  early  youth.  In  the  East  Indies  there  are  two 
seasons  for  pearl  fishing ;  the  first  in  March  and  April,  the 


402  A   POPULAR   TREATISE    (N    GEMS. 

second  in  August  and  September ;  and  the  more  rain,  the 
more  productive  are  the  pearl  fisheries.  In  the  beginning 
of  the  season  there  are  sometimes  two  hundred  and  fifty 
barks  on  the  banks ;  the  larger  barks  have  two  divers,  the 
smaller,  one.  The  divers  descend  from  their  barks  with  a 
rope  round  their  body,  and  a  stone  of  twenty  or  thirty 
pounds  attached  to  one  of  their  feet,  so  that  they  may  sink 
speedily  from  eight  to  twelve  fathoms,  where  they  meet 
the  shells  fastened  to  the  rocks ;  the  nostrils  and  ears  are 
stuffed  up  with  cotton,  and  to  the  arm  a  sponge  dipped  in 
oil  is  fastened,  which  the  diver  now  and  then  brings  to  his 
mouth,  in  order  to  draw  breath  without  swallowing  water. 
He  also  carries  down  with  him  a  large  net,  tied  to  his  neck 
by  a  long  cord,  the  other  end  of  which  is  fastened  to  the 
side  of  the  vessel,  to  hold  the  shells,  and  the  cord  is  to 
draw  him  up  when  the  net  is  full,  or  when  he  wants  air ; 
he  has  likewise  a  knife  or  an  iron  rake,  for  detaching  the 
the  shells  from  the  rocks.  Thus  equipped,  he  precipitates 
himself  to  the  desired  depth,  where  he  can  very  distinctly 
see  all  that  is  passing  around,  yet  cannot  escape  in  time  the 
sudden  approach  of  sharks,  to  whom  he  too  often  becomes 
a  prey.  When  the  diver  has  been  in  water  some  minutes, 
and  has  his  net  filled,  or  is  unable  to  stay  any  longer,  he 
loosens  quickly  the  stone  at  his  foot,  shakes  the  line,  and 
he  is  drawn  up  by  his  companions.  The  diving-bell  is  now 
frequently  used ;  more  so  than  in  former  years. 

In  the  Persian  Gulf  the  divers  rub  their  bodies  with  oil, 
and  fasten  a  stone  of  about  fifty  pounds  to  their  feet. 

The  shells  obtained  are  piled  up  in  heaps,  and  left  ex- 
posed to  the  rain  and  sun  until  the  body  of  the  animal 
putrefies,  and  they  open  of  themselves.  Those  containing 
any  pearls  have  from  eight  to  twelve.  After  being  picked 
out,  washed,  and  dried,  they  are  passed  through  nine  sieves 
of  different  sizes. 


PEARLS.  403 

At  the  Pearl  Islands,  near  the  Isthmus  of  Panama,  the 
pearl  fisheries  have,  within  a  few  years  past,  become  a 
lucrative  business  to  many  of  the  inhabitants.  The  clivers 
use  more  simple  methods  than  those  we  have  mentioned, 
for  collecting  the  pearl  oysters :  they  traverse  the  bay  in 
canoes  that  hold  eight  men,  all  of  whom  dive  naked  into 
the  water,  from  eight  to  ten  fathoms  deep,  where  they 
remain  about  two  minutes,  during  which  time  they  collect 
all  they  can  with  their  hands,  and  dexterously  rise  to- 
deposit  them  in  their  canoe,  repeating  the  operation  for 
several  hours. 

In  Sweden,  the  pearl  oyster  is  caught  with  a  pair  of 
long  tongs.  The  fishermen  are  in  small  boats,  painted 
white  on  the  bottom,  which  reflects  the  light  to  a  great 
depth,  and  as  soon  as  they  perceive  them  passing  under- 
neath they  seize  the  oyster. 

Pearls  are  esteemed  according  to  their  size,  form,  color, 
and  lustre ;  the  largest,  of  the  size  of  a  small  walnut,  are 
called  paragons,  which  are  very  rare ;  those  the  size  of  a 
cherry,  are  found  more  frequently,  but  still  are  rare ;  they 
are  the  diadem  or  bead  pearls.  They  receive  names,  also, 
according  to  their  form,  whether  quite  round,  semi-circular, 
and  drum-form,  or  that  of  an  ear-drop,  pear^  onion,  or  as 
they  are  otherwise  irregularly  shaped.  The  small  pearls 
are  called  ounce  pearls,  on  account  of  being  sold  by  weight, 
and  the  very  smallest,  seed  pearls.  Those  of  a  brilliant 
white  color,  or  white  water,  are  most  sought  for  in  Europe ; 
those  of  a  yellowish  color  in  some  parts  of  Asia ;  and  some 
of  a  lead  color,  or  those  of  a  j«t  black,  are  preferred  among 
some  nations.  They  all  turn  more  or  less  yellow  with  age, 
and  to  restore  the  white  color,  they  are  either  baked  in 
bread,  rubbed  with  boiled  salted  rice,  or  kept  for  a  short 
time  in  the  gastric  juice  of  fresh-killed  chickens. 

Pearls  are  sold  by  weight — troy  weight  j  but  the  penny- 


404          -A  POPULAR  TREATISE  ON  GEMS.       „ 

weight  of  twenty-four  grains  is  counted  as  thirty ;  so  that 
an  ounce  has  six  hundred  grains,  pearl  weight,  and  four 
troy  grains  are  equal  to  five  pearl  grains.  The  price 
has,  within  the  last  forty  years,  much  diminished,  for  two 
reasons : 

1st.  Diamonds,  and  particularly  brilliants,  have  become 
more  plentiful,  and  have  since  been  worn,  not  by  the  higher 
classes  alone,  but  also  by  the  middling. 

2d.  Within  the  last  twenty  years,  artificial  pearls  have 
been  manufactured  in  high  perfection,  and  are  worn  to  a 
great  extent. 

It  is  my  opinion,  however,  that  the  price  of  pearls  will 
take  a  fresh  rise  among  the  nobility  and  richer  classes, 
diamonds  being  now  so  generally  worn ;  as  persons,  think- 
ing to  invest  safely,  without  any  future  loss,  their  surplus 
capital,  purchase  brilliants  that  formerly  were  possessed 
exclusively  by  the  rich.  • 

Pearl  fisheries  were  first  carried  on  in  remote  times  in 
the  Persian  Gulf,  and  the  most  celebrated,  formerly,  were 
near  the  island  Bahreim.  Five  hundred  thousand  ducats 
was  then  the  yearly  produce.  About  one  million  dollars' 
worth,  at  the  present  time,  are  exported.  The  island 
Kharack  now  produces  the  most  considerable  quantity. 
The  principal  market  is  at  Muscat ;  from  thence  they  are 
brought  to  Surat.  The  mode  of  procuring  them  pursued 
in  those  countries,  is  in  canoes,  holding  fifteen  men,  six  of 
whom  are  divers:  the  shells  caught  during  the  day  are 
delivered  to  a  surveyor*  when  they  are  opened  on  a  white 
cloth,  and  whoever  finds  a  pearl  of  some  value,  puts  it  in 
his  mouth,  to  give  it,  as  they  say,  a  "  better  water."  The 
greatest  harvests  are  generally  after  many  rains,  and  the 
largest  pearls  are  mostly  found  in  the  deepest  water.  At 
Ceylon  the  pearl  fisheries  are  now  considerable,  particularly 
in  the  bay  of  Condatchy.  The  shells  are  there  left  to 


PEARLS.  405 

reach  the  age  of  seven  or  eight  years,  and  in  the  fourth 
year  they  have  small  pearls,  sometimes  a  hundred  and  fifty. 
They  fish  yearly,  in  the  month  of  May,  during  four  weeks. 
In  the  year  1804,  eight  hundred  canoes,  each  with  two 
divers,  were  engaged.  Before  the  year  1800,  the  pearl 
banks  were  leased,  to  an  Indian  merchant,  for  three  hun- 
dred thousand  pagods ;  and  before  the  arrival  of  the  Euro- 
peans in  India,  the  same  bank  was  used  every  twenty  or 
twenty-four  years ;  when  under  the  Portuguese,.every  ten, 
and  under  the  Dutch,  every  six  years.  In  1800,  the 
produce  was  from  one  hundred  to  one  hundred  and  fifty 
thousand  pounds  sterling. 

Japan  has  some  pearl  banks,  which  are,  however,  not 
much  sought ;  the  same  may  be  said  of  the  Nipthoa  lake,  in 
Chinese  Tartary.  America  sent,  in  the  sixteenth  century, 
pearls  to  the  amount  of  eight  hundred  thousand  dollars  to 
Europe.  The  shells  were  mostly  collected  from  Cape  Paria 
to  Cape  Velo ;  round  the  islands  Margarita,  Cubagua, 
Coche  Punta,  Aragy,  and  at  the  mouth  of  Rio  la  Hacha," 
from  which  latter  locality,  and  the  Bay  of  Panama,  Europe 
is  now  mostly  supplied.  The  former  localities  have  long 
since  been  relinquished,  on  account  of  their  small  produce ; 
too  many  shells  having  been  removed  at  one  time,  thereby 
retarding  the  growth  of  pearls.  Panama  has  sent,  within 
a  few  years  past,  about  one  hundred  thousand  dollars' 
worth  of  fine  pearls  to  Europe,  the  trade  being  carried  on 
by  Messrs.  Plise,  of  Panama.  The  coast  of  Florida  is  said 
to  have  been  vefy  lucrative  to  the  Indians,  as  a  pearl 
fishery,  which,  however,  does  not  prove  so  now,  since  the 
settlement  of  civilized  people. 

England  used  to  be  supplied  from  the  river  Con  way,  in 
Wales ;  and  Scotland  supplied  the  London  market,  between 
the  years  1761  and  1764,  to  the  amount  of  ten  thousand 
pounds  sterling ;  but  the  supply  has  failed.  Pearls  are 


406          A  POPULAR  TREATISE  ON  GEMS. 

found  in  the  Elster  river,  in  the  kingdom  of  Saxony,  from 
its  source  at  the  borders  of  Bohemia  to  Elsterberg,  where 
the  fishery  has  been  jcarried  on  since  1(521,  with  some  ad- 
vantage to  the  sovereign ;  some  pearls  found  there  were 
valued  at  fifty  Prussian  dollars  each.  In  the  river  Watawa, 
in  Bohemia,  and  in  the  Moldau  river,  from  Kruman  to 
Frauenburg,  pearls  are  found  of  great  beauty;  so  much  so 
as  to  equal  in  price  the  Oriental  pearls.  Also,  at  Rosenberg, 
pearls  are*  sometimes  found  superior  to  the  Oriental  in 
lustre ;  and  at  Oelsnitz,  a  considerable  pearl  fishery  is  car- 
ried on.  Most  of  the  rivers  in  Sweden,  Lapland,  Finland, 
Poland,  Norway,  Jutland,  Silesia,  and  other  places,  contain 
pearls,  but  they  are  not  collected. 

It  is  a  "fact  that  the  pearl  is  equally  hard  throughout  all 
.  its  concretional  layers,  for  by  putting  the  pearl  in  a  weak 
acid,  the  outside  layer  becomes  gelatinous,  arid  the  suc- 
ceeding layers  are  found  to  be  equally  hard  and  uniform. 
It  is  almost  impossible,  therefore,  that  the  story  told  of 
Cleopatra  having  swallowed  a  pearl  after  being  dissolved 
in  vinegar,  should  be  true ;  besides,  if  the  pearl  had  been 
dissolved  as  quickly  as  reported,  it  would  not  have  made 
a  very  disagreeable  beverage.  Pearls  were  known,  and 
were  very  much  esteemed  by  the  Greeks  and  Romans,  and 
when  they  became  acquainted  with  the  Indies,  by  com- 
mercial intercourse  and  conquest,  they  preferred  the  pearls 
of  the  East  to  those  that  were  obtained  from  the  rivers  of 
Europe,  or  even  from  the  Mediterranean. 

With  the  ancients  the  wearing  of  this  species  of  curiosity 
became  a  passion  and  even  a  folly.  Necklaces,  bracelets, 
and  ear-rings  were  then  worn  in  profusion ;  dresses,  head 
and  foot  ornaments  were  manufactured  with  pearls.  Mil- 
lions of  sesterces  (a  Roman  coin  of  two  hundred  francs 
value),  were  expended  and  lavished  for  the  best  and  most 
extraordinary  pearls.  The  two  pearls  of  Cleopatra  cost 


PEARLS.  407 

nearly  two  millions  of  francs ;  Julius  Caesar  presented  to 
Servilia,  the  sister  of  the  celebrated  Cato,  of  Utica,  a  pearl 
which  he  purchased  for  one  million  two  hundred  thousand 
francs-. 

Lollia  Paulina,  the  wife  of  Caligula,  wore  ornaments  to 
the  value  of  eight  millions  of  francs.  The  ladies  went  so 
far  as  to  ornament  their  buskins  with  pearls.  Nero  lav- 
ished pearls  upon  his  lewd  women.  In  modern  times 
Buckingham  distributed  in  the  halls  of  the  Empress  Ann, 
of  Austria,  and  of  King  Louis  XIII.,  pearls  to  the  value  of 
three  hundred  thousand  francs. 

The  baroques,  which  are  excrescences  in  the  mother  of 
pearl,  are  sometimes  very  large,  and  display  some  extraor- 
dinary figures  and  inconceivable  freaks  of  nature.  They 
are  held  in  high  estimation,  and  are  mostly  worn  in  Spain 
and  Poland. 

Caire,  the  celebrated  French  jeweller,  possesses  many 
baroques ;  one  representing  a  bearded  dog ;  another,  rep- 
resenting the  order  of  the  fleece. "  He  had  a  mother  of 
pearl  containing  a  large  excrescence,  representing  a  Chinese 
with  crossed  legs. 

The  prices  of  pearls,  from  one  carat  upwards,  were  for- 
merly determined  like  those  of  diamonds,  viz :  if  the  carat 
b«  fixed  at  five  dollars,  and  a  pearl  weighs  four  carats,  take 
the  square,  or  sixteen,  which  multiplied  by  five  is  equal  to 
eighty;  so  that  a  pearl  of  four  carats  was  estimated  at 
eighty  dollars. 

At  present  the  following  are  the  prices  of  pearls : 
1  grain  is  worth,  in  France,  4  francs  per  carat. 
9     K  «  c         |0     it  " 

3  "  "  "         25     "  u 

4  "  (1  carat)  "         50     "  " 

The  baroque  pearls  are  sold  at  from  three  hundred  to 
one  thousand  francs  per  ounce. 


408          A  POPULAR  TREATISE  ON  GEMS. 

The  seed  pearls,  when  quite  round,  are  worth  about  one 
hundred  and  twenty  francs  per  ounce. 

In  France,  perforated  pearls  are  valued  at  twice  the 
prices  given  above.  The  piercing  of  the  pearl  is  well  un- 
derstood in  the  Indies.  The  value  of  a  pearl  is  always 
enhanced  by  size,  perfection,  and  color ;  those  that  have  a 
yellowish-white,  or  silver-white,  or  very  pale  gold-yellow 
shade,  or  a  rose  or  lilac  color,  are  the  most  esteemed 
pearls. 

The  French  pearl  fisheries  produce  at  least  from  three  to 
•four  millions  of  franco. 

The  French  Crown  possesses  pearls  of  immense  value : 

One  round  virgin  pearl,  of  a  magnificent  orient,  weighing, 
27T5g-  carats,  is  valued  at  two  hundred  thousand  francs.  Two 
pear-shaped  pearls,  well  formed,  of  a  beautiful  orient,  and 
weighing  together  57y^  carats,  are  valued  at  three  hundred 
thousand  francs;  two  ear-drops,  weighing  99T6^  carats,  are 
valued  at  sixty-four  thousand  francs. 

About  seventy-two  more  large  pearls,  of  great  beauty 
and  exquisite  form,  pear-shaped  and  round,  valued  in  the 
aggregate  sum  of  three  hundred  and  fifty  thousand  francs. 

At  the  Paris  Exhibition,  in  1855,  an  enormous  pearl,  of 
pear-shape,  brought  from  Berlin,  by  Napoleon  I.,  was 
exhibited. 

The  Princess  Royal  of  England,  at  her  marriage  to 
Prince  Frederic  William,  of  Prussia,  .wore  a  necklace  of 
the  finest  pearls,  which  cost,  at  the  least  calculation,  five 
hundred  thousand  francs. 

The  Emperor  Rudolph  possessed  a  pearl  weighing  one 
hundred  and  twenty  grains. 

King  Philip  II.,  of  Spain,  possessed  a  pear-shaped  pearl 
of  the  size  of  a  pigeon's  egg,  weighing  one  hundred  and 
thirty-four  grains.  It  came  from  Panama,  and  was  valued 
at  fifty  thousand  ducats.  It  was  called  the  Peregrina. 


PEAKLS.  409 

In  1620,  King  Philip  IV.,  of  Spain,  purchased  a  pear- 
ehaped  pearl  from  Gougitas,  of  Calais,  which  weighed  four 
hundred  and  eighty  grains.  An  anecdote  is  told  of  the 
King,  who  asked  the  merchant  how  he  could  risk  his  whole 
fortune  in  so  small  a  piece  as  that  pearl ;  whereupon  the 
merchant  replied,  that  he  knew  there  was  one  king  of 
Spain  in  the  world  who  could  afford  to  purchase  it.  It 
now  belongs  to  the  Princess  Youssopoff. 

A  costly  collection  of  pearls  from  the  Indies,  Ceylon, 
and  Singapore,  and  innumerable  pieces  of  ornamental  jew- 
elry set  with  most  costly  pearls,  was  exhibited  at  the  Lon- 
don Exhibition  by  Messrs.  Garrard,  Hunt,  Roskell,  and 
other  jewellers. 

A  large  pearl,  from  Vermont,  United  States,  weighing 
eleven  carats,  and  very  round,  but  not  of  bright  color,  is 
in  the  possession  of  Mr.  S.  H.  Palmer. 

Messrs.  Blogg  &  Martin,  of  London,  inform  me,  under 
date  of  April  25,  1859,  that  they  have  in  their  possession  a 
magnificent  pearl  necklace,  consisting  of  thirty-seven  per- 
fect pearls,  of  forty  grains  each ;  they  sent  a  description  of 
it,  and  also  of  two  beautiful  pearl-drops,  which  they  value 
at  two  thousand  pounds  sterling.  The  necklace  and  drops, 
which  must  be  unique  specimens,  deserve  more  than  "a 
mere  notice,  but  the  description  came  too  late  for  insertion. 

United  States  Pearls. 

New  Jersey  merits  the  credit  of  producing  fine  pearls  ; 
a  great  many  thousand  pearls  have  been  obtained  from  the 
mussels,  which  compare  fairly  with  those  of  the  India  pearl- 
shell  ;  size,  color,  nacre,  and  orient  are  displayed  in  many 
of  the  New  Jersey  pearls  in  a  high  degree,  and  are  now 
passing  in  Europe  for  the  genuine  Oriental  or  Panama 
pearls.  In  1857,  a  shoemaker  named  David  How  ell,  living 

18 


410 


A  POPULAR  TREATISE  ON  GEMS. 


Fig.  14. 


PEAHLS. 


411 


Fig.  12  J. 


Fig.  15. 


Fig.  16. 


412  A  POPULAR  TREATISE   ON   GEMS. 

near  the  town  of  Paterson,  New  Jersey,  went  to  a  neighbor- 
ing brook,  called  Notch  brook,  in  order  to  collect  some 
mussels  for  his  breakfast,  and,  on  opening  them,  discovered 
a  great  many  loose  pearls  falling  out,  which  he  took  to  a 
jeweller  in  Paterson,  who  stated  to  him  that  they  were 
valuable,  and  they  both  began  to  collect  millions  of  these 
mussels,  and  their  efforts  were  crowned  with  success.  The 
preceding  representation  of  the  mussel  belongs  to  the  great 
family  of  unio,  which  was  formerly  called  the  avicula  mar 
garitifera,  mya  margaritifera,  but  now  known  as  an  alas- 
madonta  arcuata — named  by  Barnes.  Many  unios  (of 
which  there  are,  according  to  Lea,  Say,  and  other  Ameri- 
can conchologists,  over  six  hundred  species),  contain  pearls 
more  or  less ;  and  Mr.  John  H.  Redfield,  the  efficient 
corresponding  secretary  of  the  New  York  Lyceum  of 
Natural  History,  informs  me  that  he  found  the  pearls  in 
the  same  locality  in  New  Jersey,  in  three  or  four  other 
unios,  such  as  the  unio  complanatus,  unio  ochraceus,  unio 
radiatus,  &c.  A  very  perfect  pearl  in  the  shell  may  be 
seen  in  the  annexed  drawing,  which  is  copied  from  "  Frank 
Leslie's  Illustrated  News"  of  May,  1857;  the  pearl  is  rather 
dark,  and  the  shell,  as  may  be  seen,  appears  worn  off. 
This  is  one  of  the  characteristics  of  the  shells  containing 
pearls,  and  it  appears  to  indicate  that  the  animal  is  in  the 
decline  of  life,  and  that  the  mussel  is  becoming  gradually 
decayed. 

The  streams  in  which  these  pearl  shells  are  found  are 
generally  very  shallow,  not  more  than  one  or  two  feet 
deep,  and  the  shells  may  be  picked  up  with  the  hands; 
many  thousand  shells  are  opened,  containing  deposits  of 
the  pearly  matter,  most  of  which  contains  shapeless  and 
colorless  pearls^  which  are  so  small  that  they -are  of  no 
value ;  many,  however,  contain  very  perfect  pearls ;  the 
crown-pearl,  weighing  ninety-one  grains,  in  the  possession 


PEARLS.  413 

of  Messrs.  Tiffany  &  Co.,  was  purchased  from  Mr.  Howell 
for  $1500.  This  pearl  resembles  a  crown,  having  three 
smaller  pearls  resting  upon  the  large  pearl ;  another  repre- 
sentation of  a  pearl  weighing  nearly  four  hundred  grains, 
here  represented,  was  destroyed  by  cooking  the  mussel  in. 
order  to  open  it  better,  and  the  color  of  the  nacre  has 
been  spoiled ;  it  would,  probably,  have  been  the  largest 
pearl  of  modern  times,  and  of  immense  value. 

The  alasmadonta  of  the  present  day  was  formerly  called 
mya,  from  the  Greek  fiva),  to  compress,  it  is  called  in 
English,  the  gaper,  on  account  of  the  bivalve  gaping  at  one 
end,  its  hinge  having  a  solid,  thick,  patulous  tooth,  seldom 
two,  and  not  inserted  in  the  opposite  valve;  the  same 
genus  was  originally  called  mytilus;  they  inhabit  both 
the  ocean  and  fresh  water;  they  perforate  the  sand  or 
mud  at  the  bottom.  Many  species  are  caught  for  food, 
and  others  for  the  pearls;  some  few  of  the  same  genus 
perforate  and  live  in  limestone,  like  the  pholadites. 

The  pearl-bearing  mya,  now  alasmadonta,  is  frequently 
found  in  the  large  rivers  of  northern  latitudes.  The  Brit- 
ish Islands,  especially  Ireland,  were  formerly  famous  for 
their  fisheries,  and  a  few  pearls  of  great  value  have  at  times 
been  obtained  from  these  sources,  although  the  British 
specimens  are  not  held  in  high  estimation,  with  the  excep- 
tion of  a  few  procured  from,  the  river  Shannon,  in  the 
year  1821. 

The  river  Irt,  in  Cumberland,  the  Conway,  in  Wales, 
and  the  Tay,  in  Scotland,  were  once  noted  for  their  pearl 
fisheries.  Suetonius  reports  that  Caesar  was  induced  to 
undertake  his  British  expedition  for  the  sake  of  the  pearls ; 
and  according  to  Pliny  and  Tacitus,  he  brought  home  a 
buckler  made  with  British  pearls,  which  he  dedicated  to, 
and  hung  up  in  the  temple  of  the  idol  Venus  genetrix. 

The  gapers  are  mostly  used  for  food,  both  in  Britain 


414  A   POPULAR   TREATISE    ON    GEMS. 

and  on  the  Continent ;  around  Southampton,  in  England, 
these  mussels  are  known  by  the  whimsical  name  of  "  old 
maids,"  and  the  inhabitants  of  the  northern  islands  call 
them  smuslin,  and  consider  it  a  fine  supper-dish,  which  is 
by  no  means  unpalatable.* 

I  am  informed  by  Mr.  Plise,  who  brought  a  considera- 
ble quantity  of  pearls  from  Panama,  that  he  receives  four 
dollars  per  grain  in  England,  for  those  of  good  size  and 
quality. 

Pope  Leo  bought  a  pearl  for  eighty  thousand  crowns. 
Tavernier  describes  one  belonging  to  the  King  of  Persia, 
which  is  said  to  have  cost  one  million  six  hundred  thousand 
livres.  Portugal  has  a  pearl  in  her  treasury  of  the  size  of 
a  pear.  Two  Greeks,  residing  in  Moscow,  are  in  posses- 
sion of  a  pearl  weighing  twenty-seven  and  seven  eighths 
carats. 

For  restoring  Oriental  pearls  to  their  original  lustre, 
which  they  lose  in  the  course  of  time,  the  following  pro- 
cess is  resorted  to  in  Ceylon :  the  pearls  are  allowed  to  be 
swallowed  by  chickens,  which  are  then  killed,  and  the 
pearls  are  an  hour  afterwards  taken  out  of  the  stomach, 
when  they  are  as  white  and  as  lustry  as  if  just  taken  from 
the  shell. 


The  poet  Cowper  thus  expatiates  on  the  mussel: 

"  Condemn'd  to  dwell 
Forever  in  his  native  cell ; 
Ordain'd  to  move  where  others  please, 
Not  for  his  own  content  or  ease  ; 
But  toss'd  and  buffeted  about, 
Now  in  the  water  and  now  out ; 
Yet  in  his  grotto-work  inclosed 
•         He  nothing  feels  in  that  rough  coat, 
Save  when  the  knife  is  at  his  throat; 
Wherever  driven  by  wind  or  tide, 
Exempt  from  every  ill  beside." 


PEAELS.  415 

Artificial  Pearls. 

Artificial  pearls  or  beads  are  of  various  kinds;  most 
generally  they  consist  of  solid  masses  of  glass,  with  a  hole 
drilled  in  them  ;  or  they  are  blown  hollow,  and  then  filled 
out  with  metallic  lustry  grains,  wax,  or  with  the  fine  scales 
of  the  bleak  fish,  which  have  a  silvery  and  pearly  lustre. 

The  art  of  imitating  pearls  is  attributed  to  a  manufac- 
turer of  beads,  of  the  name  of  Janin  or  Jalquin,  who  lived 
at  Paris  in  1680;  he  was  led  to  the  discovery  by  seeing, 
one  day,  the  scales  of  the  bleak  fish  swimming  in  a  trough, 
where  the  fish  detached  them  by  rubbing  against  each 
other,  and  he  at  once  conceived  the  idea  of  applying  these 
scales  for  imitating  the  orient  of  the  pearls,  by  mixing 
them  with  a  mucilage  and  filling  the  interior  of  hollow 
glass  bulbs,  and  he  gave  this  natural  and  wonderful  pro- 
duction the  name  of  Extract  of  Orient — a  very  singular 
name,  but  still  significant  of  the  meaning  of  its  employment. 
It  is  well  known  that  this  little  white  fish,  the  bleak,  is 
found  in  abundance  in  the  rivers  Seine  and  Marne,  in 
France,  and  in  many  small  rivers  in  Sweden,  Germany, 
and  Italy.  The  bleak  fish  fructifies  around  water-mills, 
where  they  are  caught  by  nets. 

For  the  purpose  of  extracting  the  color  of  the  scales  of 
the  fish,  they  are  rubbed  pretty  hard  in  the  fresh  water 
collected  in  a  stone  basin,  which  settles  down  in  the  bottom 
of  this  vessel ;  the  sediment  is  then  pressed  out  through 
a  linen  rag,  and  they  are  then  replaced  again  in  fresh 
water  and  left  there  to  settle  for  several  days,  when  the 
water  is  drawn  off  and  the  precipitate  is  carefully  collected ; 
this  is  called  the  extract  or  essence,  and  it  requires  from 
seventeen  to  eighteen  thousand  fishes  to  obtain  five  hun 
dred  grammes  (a  little  over  one  pound). 

The  scales  being  animal  matter  are,  therefore,  liable  to 


416  A   POPULAR   TREATISE    ON    GEMS. 

decomposition,  and  for  their  preservation  numerous  chemi- 
cal agents  have  been  employed  by  the  different  manufac- 
turers, all  of  whom,  who  have  succeeded,  keep  it  a  secret ; 
it  is,  however,  known  that  liquid  ammonia  is  added  to  the 
paste  of  the  scales.  . 

The  operation  of  the  manufacture  is  very  difficult,  but 
an  experienced  workman  can  manufacture  six  thousand 
pearls  in  a  day. 

The  chemists  have  experimented  for  some  years  to  imi- 
tate the  extract  of  orient, — as  it  requires  such  a  large 
quantity  of  fishes  to  obtain  any  amount  of  the  scales, — and 
according  to  Mr.  Barbot,  the  following  preparation  has 
produced  a  favorable  result :  which  is  by  distilling  one  part 
of  oxide  of  bismuth  and  two  parts  of  corrosive  sublimate ; 
the  product  is  a  species  of  butter,  which  on  redistilling 
yields  metallic  quicksilver  and  a  very  fine  powder ;  this  is 
the  substance  used  for  orientalizing  or  coating  the  artificial 
pearls  with  the  true  gloss- of  an  Oriental  pearl. 

The  same  scales  are  likewise  used  to  coat  beads  of  gyp- 
sum, or  alabaster,  which  are  soaked  in  oil  and  then  covered 
with  wax  to  give  them  a  pearly  appearance.  The  Roman 
beads  are  made  in  this  manner :  the  scales  are  dissolved 
either  in  liquid  ammonia,-  or  vinegar,  and  the  solution  or 
liquid  is  used  for  covering  those  artificial  beads.  The  Turk- 
ish rose-beads  are  made  of  an  odoriferous  paste,  and  are 
turned  afterwards  like  those  of  coral,  amber,  agate,  or 
other  hard  substances.  The  knitting  beads  are  sold  in 
meshes  of  one  hundred  and  fifty,  or  twenty  strings,  of 
fifty  beads  each,  of  various  colors ;  and  the  large  glass- 
beads  in  meshes  of  twelve  strings.  There  are  numerous 
manufactories  in  Germany  and  Italy  of  the  various  kinds 
of  beads,  which  are  used  to  a  very  great  extent  both  in 
Africa  and  North  and  South  America.  Germany  exports 
yearly  from  its  different  manufacturing  places,  such  as 


PEARLS.  417 

Heidelberg,  Nuremberg,  Sonnenberg,  Meistersdorf,  in  Bo- 
hemia, and  Mayence,  more  than  a  million  dollars'  worth. 
In  Venice  are  large  establishments  for  the  finest  cut  beads. 

Nuremberg  manufactures,  besides  glass  beads,  consid- 
erable quantities  of  amber  beads.  In  Gablontz,  in  Bohe- 
mia, more  than  six  thousand  persons  are  engaged  in  the 
manufacture  of  beads,  that  are  made  of  pure  glass,  or  of  a 
composition.  From  the  glass-houses,  which  are  very 
numerous  in  Bohemia,  the  rods  of  different  sizes  are 
delivered  to  the  glass  mills  for  cutting,  which  is  performed 
by  water  power  or  by  hand.  In  1828  there  were  in  that 
neighborhood  one  hundred  and  fifty-two  mills  in  operation; 
a  number  of  glass-blowers  were  likewise  engaged,  who 
possessed  great  dexterity  in  blowing  the  small  beads  with 
the  assistance  of  a  small  blow-table.  In  the  manufactory  of 
George  Benedict  Barbaria,  at  Venice,  six  hundred  varieties 
of  beads  are  constantly  making ;  and  that  of  Messrs.  Gas- 
pari  and  Moravia  manufactures,  besides  the  beads,  every 
article  of  jewelry  from  the  same  material. 

The  rose  beads  of  Steffansky  and  Tausig,  are  made  of 
bread  crumbs,  which  are  beaten  up  with  rose  water  in  a 
wooden  mortar,  until  they  become  a  uniform  mass,  to 
which  is  added  some  otto  of  roses  and  drop-lake,  when  it  is 
made  into  beads  with  dissolved  gum  tragacanth ;  for  the . 
black  rose-beads,  Frankford  black  is  substituted  hi  the 
place  of  the  drop-lake. 

Lamaire,  of  France,  manufactures  beatfs  equal  in  lustre 
and  beauty  to  real  pearls.    He  adds  to 
1000  ounces  of  glass  beads, 

3       "          scales  of  the  bleak-fish, 
^        "  fine  parchment  glue, 

1        "  white  wax, 

1        "          pulverized  alabaster, 
with  which  he  gives  them  an  external  coating. 

18° 


418  A   POPULAR   TREATISE   ON   GEMS. 

Rouyer  manufactures  his  beads,  also  in  France,  from 
opal,  which  he  covers  with  four  or  five  layers  of  dissolved 
isinglass,  and  then  with  a  mixture  of  a  fat  oil,  spirits  of 
turpentine,  and  copal,  so  as  to  prevent  their  becoming 
moist.  In  order  to  render  them  of  the  peculiar  lustre  of 
the  Oriental  pearls,  they  are  covered  with  a  colored  enamel. 
The  opal  is  fused  into  rods  by  a  lamp,  over  which  is  laid  a 
brass  wire  to  support  it ;  the  wire  is  held  in  one  hand  and 
the  opal  in  the  other,  and  the  wire  is  then  kept  turning 
until  the  bead  has  the  desired  size  and  .roundness;  if  a 
colored  enamel  is  to  be  applied,  the  beads  are  made  but 
half  the  required  size,  which  being  done,  they  are  once 
more  covered  with  the  opal,  then  the  solution  of  isinglass 
is  used,  and  lastly  the  varnish.  Beads  made  in  this  man- 
ner are  with  difficulty  distinguished  from  the  Oriental 
pearls. 

The  best  method  of  making  artificial  pearls,  is  certainly 
by  means  of  pulverized  real  pearls.  Either  the  smallest,  or 
the  deformed  large  specimens,  may  be  reduced  to  a  fine 
powder,  and  then  soaked  in  vinegar  or  lemon-juice,  and 
the  paste  made  up  with  gum  tragacanth ;  they  may  then  be 
cut  out  with  a  pill  machine,  or  a  silver  mould,  of  any  desired 
size,  and  when  a  little  dry,  inclosed  in  a  loaf  and  baked  in 
an  oven :  by  tin  amalgam,  or  by  the  silver  of  the  scales  of 
young  fish,  the  proper  lustre  may  be  given. 

The  artificial  pearls,  by  Constant  Vales  &  E.  Truchy,  of 
Paris,  which  were  on  exhibition  in  the  London  Crystal 
Palace,  were  extremely  beautiful,  and  were  with  the 
greatest  difficulty  distinguished  from  the  natural  pearls. 

Messrs.  Bouillette,  Hyvelei  &  Co.,  of  Paris,  exhibited, 
besides  many  beautiful  pearls,  a  great  variety  of  artificial 
stones,  all  of  their  own  manufacture,  and  very  tastefully 
set ;  among  them  was  a  stomacher  in  diamonds,  pearls,  and 
emeralds. 


CORALS.  419 

The  shad-fish,  as  well  as  the  white-fish  of  our  lakes,  must 
yield  an  extract  of  orient,  of  as  good  a  quality  as  the  bleak- 
fish  of  the  Seine,  and  it  is  to  be  hoped  that  some  enter- 
prising mechanic  may  take  an  opportunity  of  preparing  the 
white  matter  adhering  to  the  scales  of  the  fish  just  men- 
tioned, either  for  export,  or  for  the  purpose  of  imitating 
pearls,  which  may  be  done  as  well  in  this  country  as  any- 
where else. 

The  usual  price  of  false  pearls  is  two  dollars  and  fifty 
cents  a  string, — one  hundred  to  the  string ;  but  some  are 
lower,  and  some  higher,  according  to  color. 

CORALS. 

Corals  are  zoophytes,  whose  calcareous  habitations  resem- 
ble vegetable  branches.  They  live  in  the  sea,  adhering  to 
rocks,  stones,  or  vegetables,  and  shoot  to  the  surface  of  the 
water  in  tnbiform  stems  with  branches,  generally  coated 
with  a  gelatinous  or  leathery  skin  that  incloses  a  cartilagi- 
nous marrow,  composed  of  many  cells,  inhabited  by  the 
animals, — who  propagate  in  sprouts  from  eggs  so  fast,  that 
small  reef-rocks  are  formed,  which  in  the  course  of  time 
become  islands. 

The  red  coral,  or  precious  coral  (iris  nobilis),  belongs  to 
that  family  of  zoophytes  which  live  mostly  in  the  cavities 
of  rocks  in  the  sea ;  the  stem  is  always  of  a  beautiful  red 
color,  rarely  white ;  quite  compact,  striated  on  the  outside, 
of  entire  calcareous  composition ;  it  grows  one  foot  high 
and  an  inch  thick.  The  stem  is  covered  with  a  leathery 
crust,  containing  open  warts  of  eight  teeth,  in  which  the 
animals,  or  polypi,  with  their  eight  arms,  are  situated ;  the 
arms  are  whimpered,  and  the  animal  grows  very  slowly. 

The  red  coral  is  fished  up  with  nets  of  strong  ropes,  fas- 
tened on  large  wooden  cross-beams,  which  are  thrown 


420          A  POPULAR  TREATISE  ON  GEMS. 

down  on  the  places  where  the  corals  are  known  to  be  fas- 
tened, and  an  expert  diver  contrives  to  entangle  the  nets 
in  the  reefs,  which  are  then  drawn  up  by  force.  The  corals 
so  brought  up  are  cleaned,  assorted,  and  sold  to  the  manu- 
facturers. 

Messrs.  Payenne  &  Laminal  have  invented  a  very  inge- 
nious machine  for  collecting  the  coral  from  the  banks  of 
the  ocean,  without  breaking  the  fine  branches  and  without 
injuring  the  banks  which  are  formed  for  the  growth  of  the 
coral. 

It  is  a  fact  admitted  by  naturalists  and  fishermen,  that 
the  growth  and  accumulation  of  the  zoophytes  take  place 
continually  in  the  same  waters ;  and  that  as  great  and  pro- 
lific a  traffic  may  be  created  by  coral  catching  as  by  the  fish- 
eries in  France.  Lord  Ellis  proved,  in  1754,  that  the  coral 
polype  possesses  an  ovarium  filled  with  small  eggs,  pre- 
pared for  hatching ;  all  these  eggs  are  attached  together 
by  a  species  of  cordon,  and  resemble  worms ;  tentacles  are 
shooting  out  from  them,  which  move  in  the  same  manner 
a$  the  grown  polypes. 

In  3856,  Mr.  Focillon  presented  a  report  to  the  Acclimi- 
tation  Society  at  Paris,  on  the  methodical  exploration  of 
the  ancient  and  natural  banks,  and  on  the  construction  of 
artificial  coral  banks  in  such  a  manner  as  to  secure  the 
most  favorable  position  for  the  production  and  operation 
of  an  easy  and  sure  coral  harvest.  Facts  have  already 
been  elicited,  that  the  new  coral  succeeds  so  well  at  a 
depth  of  seven  to  eight  metres  (twenty  four  feet),  under 
the  influence  of  the  rays  of  the  sun,  that  it  develops  quickly, 
and  becomes  large  and  of  good  color  at  the  end  of  eight  or 
nine  years;  while  a  coral  at  a  depth  of  thirty  to  fifty 
metres  (one  hundred  and  fifty  feet),  requires  from  thirty- 
five  to  forty  years  to  shoot  out,  and  it  is  not  then  of  as 
good  a  color  as  the  former.  This  discovery  ought  to 


COEALS.  421 

stimulate  the  African  coast  (Algeria),  particularly  the  in 
habitants  on  the  shores  of  Bona,  Oran,  and  other  places, 
who  ought  to  be  beforehand  in  the  application ;  also  on  the 
Marseilles  coast,  which  is  already  full  of  coral  reefs. . 

Coral  was  formerly  cut  in  facets,  and  was  in  great  favor 
under  the  consulate  and  empire  of  France,  for  almost  every 
species  of  luxury ;  combs,  ear-rings,  necklaces,  beads, 
crosses,  &c.,  were  manufactured  and  sold  at  high  prices ;  but 
the  fashion  and  price  soon  fell.  Ten  or  fifteen  years  after- 
wards an  endeavor  was  made  to  bring  coral  in  vogue  again, 
by  offering  coral  engraved  as  cameo,  and  made  into  other 
ornaments, — such  as  brooches,  bracelets,  ear-rings,  and  pins, 
which  were  then  sold  pretty  high ;  but  on  account  of  an 
insufficient  supply  of  the  article  and  bad  workmanship,  it 
fell  back  to  its  original  lethargy,  and  for  many  years  it  was 
considered  worthless  and  altogether  out  of  fashion. 

During  the  last  two  years,  coral  has  resuscitated  very 
much,  and  got  into  good  grace  with  the  ladies. 

The  Parisians  have,  however,  changed  their  taste  for  the 
former  favorite, — the  red  coral ;  the  rose-colored,  cut  in  a 
round  form,  so  as  to  nearly  resemble  a  rose  pearl,  being 
preferred,  which  is  acknowledged  to  be  extremely  rare. 
The  price  of  these  rose'-colored  corals  has  of  late  risen  so 
high,  that  a  fabulous  sum  is  paid  for  them;  and  a  coral 
which  was  worth  but  fifty  francs  in  1810,  is  now  sold  for 
three  hundred  francs  and  upwards.  At  present  the  fashion 
for  corals  is  at  its  height,  and  ornaments  of  every  con- 
ceivable variety  may  be  seen  in  the  shops  of  jewellers  in 
this  country,  imported  from  France  and  Italy.  . 

At  the  last  Paris  Exhibition  there  was  a  coral  chess- 
board, with  all  its  figures  representing  an  army  of  Cru- 
saders and  of  Saracens,  which  was  admirably  executed,  and 
valued  at  10,000  francs.  Coral  branches,  if.  without  a  frac- 
ture, bring  a  great  price. 


422          A  POPULAR  TREATISE  ON  GEMS. 

France  manufactures  and  exports  coral  ornaments  to  the 
value  of  six  millions  of  francs,  and  the  demand  for  them 
is  much  greater;  the  establishments  of  Barbaroux  and 
Garaudy  &  Fils,  in  Marseilles,  where  the  coral  is  principally- 
manufactured  into  ornaments,  give  proof  that  France  will 
retain  the  supremacy  in  this  species  of  luxury. 

In  the  Paris  Exhibition  of  1855,  many  curious  sculptured 
and  chiselled  objects  were  shown  by  Arsene  Gourdin,  of 
Paris. 

In  the  London  Exhibition,  fine  corals  were  shown  from 
the  Cape  of  Good  Hope,  from  Reftaelli  &  Son,  in  Tuscany; 
from  Algiers  .was  also  a  collection.  Tucker  &  Co.,  of  Ber- 
muda, exhibited  a  fine  collection  of  both  corals  and  madre- 
pores, including  the  black  flexible  coral  (gorgonia). 
Among  the  ancient  rare  coral  engravings  is  the  head  of 
the  philosopher,  Chrysippe,  in  high  relief:  it  was  in  the 
Orleans  collection.  A  coral  cameo  of  the  14th  or  15th 
century,  representing  a  Sphinx  with  three  Cupids,  well 
executed,  is  mentioned  by  Caire. 

The  red  corals  are  distinguished  by  the  names  of  the 
countries  where  found. 

1.  The  Barbarian,  which  are  the  thickest  and  purest. 

2.  The  Corsican,  which  are  the  'darkest,  but  not  so  thick, 

and  less  pure. 

3.  The  Neapolitan,   and  those  from  Ponza,  which  are 

clear  and  pretty  thick. 

4.  The  Sardinian,  which  are  thick  and  clear. 

5.  The  Catalonian,  which  are  nearly  as  dark  as  the  Cor- 

sican, but  mostly  thin. 

6.  The  Trapanian  corals,  from  Trapani,  in  Sicily,  which 

are  somewhat  preferred  at  Leghorn. 
The  darkest  corals  are  most  liable  to  be  worm-eaten. 
The  polished  corals  are  generally  sold  in  bundles,  which 
consist  of  a  certain  quantity  of  strings,  of  a  certain  weight. 


CORALS.  423 

They  are  strung  in  Leghorn,  either  of  various  or  equal 
thicknesses,  which  latter  are  then  of  various  sizes,  and  the 
bundles  receive  their  names  accordingly;  grossezze,  mez- 
zanie,  filotti,  capiresti,  &c.  The  thickest  corals  are  put 
up  in  one  string,  resembling  a  tail,  and  are  called  codini ; 
the  smallest  are  called  smezzati. 

At  Genoa,  the  various  large  corals  are  called  mezza- 
nie  j  the  uniform  large,  filze  /  and  the  uniform  small, 
migUari. 

They  are  distinguished  according  to  color  at  Leghorn ; 
the  darkest  red  are  called  arcispiuma,  Avhich  are  the  dearest ; 
and  then  primo,  secundo,  terzo,  quarto,  coloro  or  sangue, 
chiari,  moro,  nero,  &c. 

According  to  form  they  are  called  round  (tondi),  and 
cylindrical-round  (boticelli).  The  former  are  sent  to  all 
parts  of  the  world,  but  the  latter  are  only  sent  to  Poland. 
The  large  boticelli  are  put  up  in  meshes  of  twelve  pounds, 
containing  thirty-six  strings  ;  and  the  middling  size  of  the 
boticelli  are  in  meshes  of  six  pounds,  containing  sixty 
strings;  those  boticelli  which  are  still  larger,  are  called 
olivatti,  and  are  only  sent  to  Africa ;  those  which  are  glob- 
ular, and  not  drilled,  are  called  paUini  altorni,  and  sent 
principally  to  China,  where  the  favorite  color  is  the  rose- 
red. 

The  sound  corals  are  called  netti,  and  the  worm-eaten, 
camolatti,  which  latter  are  mostly  sent  to  the  East  Indies. 

The  tops  of  the  branches  are  called  dog-teeth,  or  dents 
canines,  and  the  thick  ends  of  the  branches  are  called  mao- 
metti  •  both  kinds  are  perforated  lengthwise,  and  are  used 
in  Barbary  as  ornaments  for  horses.  The  fine  large  coral 
stems  which  form  suitable  specimens  for  cabinets  of  natural 
history,  in  Marseilles,  are  called  chouettes. 

There  are  one  hundred  varieties  of  shades  of  red  coral 
distinguished  at  Marseilles. 


424  A  POPULAR  TREATISE  ON  GEMS. 

Corals  are  principally  used  for  ornaments,  in  the  East 
Indies,  China,  and  Africa,  where  they  are  preferred  to  the 
diamond.  Almost  every  East  India  lady  wears  a  bracelet 
or  necklace  of  corals. 

The  white  coral  has  its  origin  from  the  eight-star  coral 
(rtiadrepora  occulta)]  and  the  black  coral  from  the  black- 
horned  coral  (gorgonia  antipotlies) .  The  medusa  head 
(caput  medusce),  called  the  sea  polen,  belongs  likewise  to 
the  coral  family,  and  consists  of  sixty-two  thousand  six  hun- 
dred and  sixty-six  articulated  members. 

Corals  are  fished  for  on  the  coast  of  Barbary,  between 
Tunis  and  Algiers ;  in  the  latter  state  Bona  is  the  principal 
station ;  the  French  have  one  also  at  Basteon  de  France. 

The  monopoly  was  purchased  by  France,  in  the  seven- 
teenth century,  at  eighteen  thousand  dollars  annually;  and 
by  England,  since  1806,  for  fifty  thousand  dollars. 

At  Bona  there  is  a  summer  fishery,  from  the  first  of 
April  to  the  first  of  October,  which  occupied,  in  1821, 
thirty  French,  seventy  Sardinian,  thirty-nine  Tuscanian, 
eighty-three  Neapolitan,  nineteen  Sicilian  barks ;  alto- 
gether, two  hundred  barks  of  two  thousand  and  twenty- 
three  tons  capacity,  with  two  thousand  two  hundred  and 
seventy-four  men ;  they  fished  up  forty-four  thousand  two 
hundred  pounds  of  coral,  valued  at  two  million  four  hun- 
dred thousand  francs.  The  winter  fishery  of  the  same  year 
occupied  three  French  barks,  each  with  nine  men,  and  they 
obtained  six  hundred  and  eighty  pounds  of  coral. 

The  principal  manufactories  of  corals  are  now  at  Leg- 
horn, where  this  branch  of  business  has  been  carried  on  for 
two  hundred  years  past,  by  the  Jews.  There  were  for- 
merly twenty  establishments,  but  the  number  has  lately 
been  much  diminished. 

They  are  sent  principally  to  China,  the  East  Indies,  and 
Arabia,  partly  by  the  way  of  London,  and  partly  by  Mos- 


SHELL    CAMEOS.  425 

cow,  Aleppo,  and  Alexandria;  many  corals  are  likewise 
sent  to  Poland. 

Genoa  has  a  few  manufactories,  in  which  the  Sardinian 
corals  are  mostly  wrought.  At  Marseilles  there  has  been 
a  large  manufactory  ever  since  1780,  and  at  present  it  is 
the  only  establishment  of  the  kind  in  France. 

The  East  Indies  consume,  according  to  the  statement  of 
Le  Goux  de  Haix,  nearly  four  million  francs'  worth. 

Corals  are  worn  in  the  East  as  ornaments  in  the  turban, 
and  the  Arabs  bury  the  coral  with  their  dead. 

A  large  coral,  from  the  manufactory  at  Marseilles,  was 
sold  in  China,  to  a  mandarin,  for  twenty  thousand  dollars. 

Purpurin  is  the  name  of  artificial  coral.  A  large  quan- 
tity of  this  false  and  base  imitation  of  coral  has  been  im- 
ported into  this  country.  It  is  used  for  setting  in  cheap 
jewelry;  brooches,  bracelets,  ear-rings,  and  pins  may  be 
seen  everywhere  in  this  city,  all  carved  in  figures  and  ani- 
mals, resembling  the  true  coral,  but  on  testing  it  with  a 
knife,  the  baseness  is  easily  detected.  It  is  composed  of 
marble  powder,  made  into  a  paste  by  a  very  siccative  oil 
or  varnish,  or  soluble  glass  (silicate  of  potash),  and  a  little 
isinglass,  and  colored  by  Chinese  vermilion.  The  paste 
is  then  moulded  into  the  various  objects  required,  and  when 
dry  such  parts  as  require  it  are  perfected  with  the  chisel. 

•• 

SHELL   CAMEOS. 

The  shells  employed  for  cameo-cutting,  .are  the  cassis 
rufa,  and  several  species  of  cyprea,  called  cowries.  They 
are  dense,  thick,  and  consist  of  three  layers  of  differently 
colored  shell  material.  In  the  cassis  rufa,  each  layer  is 
composed  of  many  very  thin  plates,  or  lamina?,  which  are 
perpendicular  to  the  plane  of  the  main  layer ;  each  lamina 
consists  of  a  series  of  elongated  prismatic  cells,  adherent  by 


426  A  POPULAR  TREATISE  ON  GEMS. 

their  long  sides ;  the  laminae  of  the  outer  and  inner  layers 
are  parallel  to  the  lines  of  growth,  while  those  of  the 
middle  layer  are  at  right  angles  to  them.  In  cowries 
there  is  an  additional  layer,  which  is  a  duplicature  of  the 
nacreous  layer,  formed  when  the  animal  has  attained  its 
full  growth. 

At  the  London  Exhibition  there  was  a  very  fine  collec- 
tion of  shell  cameos,  from  Rome,  owned  by  the  engraver 
Seculine. 

Certain  natives  of  India  prepare  shell  cameos  with  rude 
but  efficient  instruments  for  cutting  them,  and  the  Indian 
department  in  the  Exhibition  showed  numerous  specimens. 

MOSAIC    AND    PIETRA    DURA. 

Roman,  Venetian,  Florentine,  and  other  Mosaics. — 
The  art  of  mosaic  (opus  musivum  of  the  Romans),  was  origi- 
nally applied  only  to  the  combination  of  small  dice-shaped 
stones  (precious  and  common),  or  tessera?  of  the  ancients, 
in  patterns.  It  has  long  been  an  important  source  of  labor 
to  the  inhabitants  of  several  parts  of  Italy,  such  as  Venice ; 
and  under  various  modifications  is  now  carried  on  in  the 
principal  cities  of  Europe.  The  manufacture  has  long 
ceased  to  be  confined  to  combinations  of  tessera?,  and  is 
now  understood  to  include  all  kinds  of  inlaid  and  veneered 
work,  in  whatever  material, — fragments  of  pseudo-precious 
stones  (agate,  chalcedony,  malachite,  lapis  lazuli),  marbles 
of  the  most  variegated  colors,  porphyry,  lava,  granite, 
fluor-spar,  and  also  the  various  colored  glasses  (imitation 
gems),  avanturine,  and  enamels,  which,  when  put  together 
(sometimes  in  microscopical  fragments),  and  formed  into  a 
landscape,  figures,  or  other  design,  are  now  called  mosaics. 
The  richer  the  colors  and  shadings,  so  as  to  produce  fine 
pictures,  the  more  striking  the  mosaics  fall  on  the  eye  of 


MOSAIC   AND   PIETBA    DURA.  427 

the  spectator.  The  Roman  mosaics,  in  which  prisms  or 
threads  of  glass,  of  various  sizes  and  shapes,  compose  the 
whole  picture  ;  the  Venetian  mosaics,  where  the  glass  is  a 
tessera  or  square  shape,  of  some  size,  inlaid  often  in  a 
cement  base. 

The  manufacture  of  true  Roman  mosaics  has  always 
been  confined  to  the  city  whence  its  name  is  taken,  and  no 
country  has  entered  into  competition  with  Rome.  They 
are  composed  of  glass,  sometimes  called  smalt,  and  some- 
times paste ;  are  made  of  all  kinds  of  colors  and  every 
different  hue.  For  large  pictures  they  take  the  form  of 
small  cakes ;  for  small  works  they  are  produced  in  threads, 
varying  in  thickness  from  that  of  a  piece  of  string  to  the 
finest  cotton  thread :  large  quantities  of  these,  of  all  tints 
and  colors,  are  prepared.  A  plate  or  slab  of  copper,  marble, 
or  slate  is  then  provided,  of  the  size  and  thickness  required 
for  the  intended  work.  This  slab  is  hollowed  out  so  as  to 
resemble  the  bottom  of  a  box  or  a  tray,  to  a  depth  propor- 
tioned to  the  work;  this  may  vary  from  an  inch  to  the 
eighth,  or  even  the  sixteenth  of  an  inch,  if  the  work  is  to  be 
small.  This  hollow  is  then  filled  with  plaster  of  Paris,  well 
smoothed,  on  which  the  outline  of  the  proposed  design  is 
very  accurately  traced,  and  an  inked  pen  is  passed  over 
the  outline  to  preserve  it.  Very  few  tools  are  required  by 
the  workmen,  but  for  the  large  works,  where  comparatively 
large  pieces  are  to  be  inserted,  small  shape-cutting  ham- 
mers are  made  use  of  for  splitting  the  cakes  and  reducing 
them  to  their  proper  size  and  form ;  pincers  also,  of  differ-" 
ent  forms,  are  used  for  placing  them  equally.  In  very 
small  works,  instead  of  hammers,  sharp-pointed  pincers  are 
made  use  of,  like  those  with  which  diamonds  are  taken  up, 
and  sometimes  a  small  tool  like  a  scarpello.  The  heat  of 
an  oil  lamp  is  required,  to  enable  the  workman  to  draw  out 
the  strips  of  glass  to  the  desired  fineness,  even  to  that  of 


428  A  POPULAR  TREATISE  ON  GEMS. 

a  hair.  When  this  is  all  ready,  the  first  operation  is  to  dig 
or  scoop  out,  with  a  scarpello  of  a  proper  size,  a  small  piece 
of  plaster  of  Paris  from  the  bottom  of  the  box  or  tray, 
without  injuring  the  outline ;  this  is  filled  up  with  a  kind 
of  mastic  or  putty,  like  that  which  is  used  for  panes  of 
glass  in  the  sashes  of  a  window ;  and  the  required  piece  of 
smalt  or  glass  is  then  pressed  into  the  composition.  In  this 
way,  step  by  step,  and  from  day  to  day,  repeating  the 
operation  of  scooping  out  a  small  piece  of  plaster  of  Paris, 
and  never  losing  sight  of  the  outlines,  they  gradually  fill 
up  the  whole  tray.  In  works  of  considerable  dimensions, 
the  workmen  place  the  tray  before  them  as  painters  place 
the  canvas  on  which  they  are  painting,  and  have  the  origi- 
nal always  close  to  them.  For  smaller  works  they  sit  at  a 
table,  as  if  writing,  and  keep  the  work  flat  on  the  same. 
The  designs  used  in  these  mosaics  are  for  the  most  part 
copied  from  the  pictures  of  some  artist  of  eminence,  the 
designers  themselves  being  also  a  separate  body,  working 
for  the  mosaicisti,  who  mechanically  fill  up  the  spaces  as 
above  described.  When  the  operation  is  completed,  it  is 
passed  over  a  stone  made  perfectly  smooth  and  cleaned  of 
every  kind  of  dirt ;  it  happens,  however,  that  interstices, 
however  minute,  will  be  left  more  or  less  between  the 
several  small  pieces  of  smalt  inserted  into  the  mastic ;  these 
are  to  be  carefully  filled  up  with  heated  wax,  applied  with 
hot  iron  instruments  from  a  pallet  on  which  it  has  been 
prepared  for  the  purpose,  and  much  of  the  good  effect  and 
finish  of  the  work  will  depend  on  the  ability  and  care  of 
the  workmen  by  whom  this  operation  is  performed. 

A  most  remarkable  specimen  of  this  beautiful  art  was 
shown  at  the  London  Exhibition,  by  the  Cavaliere  Bar- 
bed  ;  it  was  a  large  round  table,  and  represented  cele- 
brated views  in  Italy;  it  was  of  singular  delicacy  and 
beauty  of  workmanship, — the  style  of  the  design,  the  ex- 


MOSAIC   AND    PIETRA    DURA.  429 

quisite  shading  of  the  colors,  the  brilliant  though  softened 
effect  of  the  group  of  views,  the  atmosphere  and  sky  of  each 
mingling  into  the  same.ethereal  tint,  which  relieved  the  eye 
and  allowed  it  to  rest  with  pleasure  on  the  separate  views : 
it  was  certainly  a  masterpiece.  The  author  never  left-  the 
Crystal  Palace  without  passing  by  the  table,  which  always 
excited  fresh  admiration. 

There  were  two  other  mosaics,  much  larger  than  the 
former,  and  different  in  style,  that  were  remarkably  fine 
specimens  of  workmanship  :  one  was  a  copy  of  a  celebrated 
picture,  by  Guercino, — a  St.  John  the  Baptist ;  and  the 
other  a  portrait  of  Pope  Boniface  the  Second. 

A  circular  table,  a  square  slab,  and  a  picture  represent- 
ing a  view  of  PaBstum,  were  likewise  among  the  Roman 
mosaics  in  the  London  Exhibition. 

Dr.  Chilton,  of  New  York,  has  a  beautiful  Roman 
mosaic  of  the  Pantheon,  about  three  inches  long. 

In  the  New  York  Exhibition,  in  1853,  the  large  pic- 
ture of  Pope  Pio  IX.,  in  medallion  size,  was  much  ad- 
mired. 

• 

In  the  Paris  Exhibition,  in  1855,  many  large  works  of 
Roman  mosaics  were  exhibited ;  one  in  particular,  belong- 
ing to  the  Duke  of  Tuscany,  required  the  constant  work 
of  fourteen  years,  and  cost  700,000  francs.  A  large  table 
in  the  rotunda  of  the  panorama,  of  rich  and  elegant  Roman 
mosaic,  cost  400,000  francs.  -^ 

The  famous  picture  of  the  Campo-vacino,  in  Home,  by 
Galand,  cost  the  artist  ten  years'  labor. 

Pietra  dura,  also  called  Florentine  mosaic,  consists  in 
the  manufacture  of  hard  stone  inlaid  in  a  slab  of  marble ; 
they  are,  for  the  most  part,  of  the  quartz  species,  such  as 
agates,  jasper,  chalcedony,  carnelian,  &c. ;  also,  lapis  lazuli, 
malachite,  and  all  such  hard  and  colored  minerals  which, 
by  their  depth  of  color  and  brilliancy  of  lustre  largely  con- 


430  A  POPULAB   TREATISE   ON   GEMS. 

tribute  to  produce  a  picture  of  a  flower  or  a  landscape,  and 
all  come  under  the  name  pietra  dura  of  the  Florentine 
school. 

In  this  kind  of  work,  a  slab  of  marble  (generally  black), 
of  the  required  dimensions,  and  about  one  eighth  to  three 
sixteenths  of  an  inch  thick,  is  prepared,  and  the  patterns  to 
be  inlaid  are  carefully  cut  out  with  a  saw  and  file.  The 
hard  stones  are  worked  into  the  required  pattern  by  the 
ordinary  methods  of  gem-cutting,  and  are  accurately  fitted 
into  the  spaces  thus  prepared,  in  a  polished  and  finished 
state ;  for  if  the  whole  were  to  be  polished  at  once,  some 
of  the  substances  being  softer  than  others,  would  be  worn 
away  too  rapidly.  The  work,  also,  is  liable  to  be  spoiled 
by  the  accidental  placing  of  one  stone  lower  than  another, 
and  mistakes  of  this  kind  will  often  lead  to  the  ruin  of  the 
whole.  After  the  surface  is  thus  prepared  it  is  veneered 
on  a  thicker  slab  and  is  then  fit  for  use.  In  point  of  diffi- 
culty of  execution,  durability,  and  taste,  this  process  of 
inlaying  in  hard  stones  or  gems  may  rank  as  the  most  im- 
portant purely  decorative  work  within  the  whole  range  of 
mineral  manufactures. 

In  order  to  illustrate  the  peculiar  mode  of  inserting  the 
different  pieces  of  agate,  jasper,  &c.,  in  these  beautiful 
works  of  art,  and  to'  show  also  to  those  not  familiar-  with 
them  the  elegant  and  simple  forms  produced,  we  give  the 
following  diagram,  showing  a  fac-simile  of  a  portion  of 
the  inlaid-work  in  one  of  the  tables  which  were  exhibited 
in  the  London  World's  Exhibition,  in  1851. 

In  this  diagram  the  dark  line  represents  the  outline  of 
the  flowers,  leaves,  &c.,  and  the  dotted  part,  the  lines 
where  the  different  pieces  forming  a  single  object  are 
joined  together.  The  extreme  delicacy  and  accuracy  of 
the  joints  can  only  be  fully  appreciated  by  the  examination 
of  the  original  specimens. 


MOSAIC  AND   PIETEA   DUEA. 


431 


Fig.  11. 

True  Florentine  mosaic,  of  fine  design  and  good  taste, 
was  in  profusion  from  Tuscany  and  St.  Petersburg. 

A  jewel-case  belonging  to  the  Empress"  of  Russia,  was 
particularly  worthy  of  notice :  it  was  constructed  of  wood, 
having  the  four  sides  and  top  covered  with  groups  of  fruit 
cut  in  pietra  dura,  in  a  style  which  may  be  called  cameo- 
mosaic  in  rather  high  relief;  the  stones  were  so  selected  as 
to  afford  perfect  fac-similes,  in  color,  size,  and  even  in  in- 
ternal structure,  of  the  fruit  they  represented,  which  were 
currants,  pears,  and  plums,  and  the  whole  work  was  ex- 
quisitely finished. 

The  King  of  Sweden  sent  to  the  London  Exhibition, 


432  A  POPULAR  TREATISE  ON  GEMS. 

an  inlaid  oblong  table  of  granite,  porphyry,  and  jasper, 
of  beautiful  workmanship ;  the  materials  were  the  hard 
stones  of  Sweden,  which  being  nearly  of  equal  hardness, 
admitted  of  being  polished  after  the  work  Was  finished. 

An  Indian  chess-table  with  an  inlaid  border,  and  a  num- 
ber of  small  objects  from  India,  the  ground  being  a  white 
marble  of  a  peculiar  saccharoidal  texture,  attracted  great 
attention.  The  pattern  was  a  fine  scroll-work,  remarkable 
for  the  extraordinary  delicacy  and  exactness  of  the  stems 
of  flowers  and  the  perfect  joints — the  stems  were  of  flint. 
This  and  another  Indian  inlaid- work  are  said  to  be  of  great 
antiquity.  No  comparison  can  be  instituted  between  these 
Indian  and 'European  works,  the  mechanical  execution  of 
the  former  being  at  least  equal  to  the  best  of  those  which 
have  rendered  Florence  so  justly  celebrated,  while  the 
taste  and  design  exhibited  in  them  are  greatly  superior  to 
inlaid  work  in  marble. 

The  great  expense  of  inlaying  hard- pebbles,  which  can 
only  be  cut  as  gems,  and  the  excellent  effect  that  may  be 
produced  by  imitations  in  which  marble  of  various  kinds, 
shells,  cement,  and  glass,  replace  the  jasper  and  agate  of 
Florentine  mosaic,  have  caused  the  introduction  into  Eng- 
land, and  elsewhere,  of  a  manufacture  which  may  be  called 
inlaid  marble  work.  In  Derbyshire  this  branch  of  manu- 
facture has  become  very  important.  There  are  two  prin- 
cipal methods  of  producing  marble  mosaic ;  that  followed 
in  Derbyshire,  where  a  recess  is  chiselled  out  of  a  solid 
block  of  marble,  serving  as  the  ground ;  and  that  pursued  in 
Devonshire,  where  the  whole  surface  is  in  fact  veneered; 
numerous  marbles  of  various  colors  and  forms  being  merely 
cemented  together  on  a  base,  which  may  consist  of  slate, 
or  any  kind  of  marble;  the  whole  surface  being  after- 
wards polished  together.  In  Malta  the  former  process  is 
followed,  while  in  Russia  the  malachite  inlaid  work  is  per- 


MOSAIC   AND    PIETRA    DURA.  433 

formed,  as  just  described.  The  Duke  of  Devonshire  loaned 
his  fine  collection  of  Florentine  mosaics  to  the  manufac- 
turers, from,  which  they  copied  the  butterflies,  leaves,  and 
sprigs  of  jessamine,  for  which  these  mosaics  are  so  cele- 
brated. These  works  being  used  as  guides,  the  art  of  in- 
laying was  brought  into  successful  operation,  and  materials 
foreign  to  the  vicinity,  as  malachite  from  Russia,  Conti- 
nental marbles,  Avanturine  and  other  glasses,  from  Venice, 
with  some  cements,  have  been  introduced  into  them.  The 
manufacturers  at  Matlock,  Ashford,  Bakewell,  Buxton, 
Derby,  and  Castleton  are  all  doing  a  thriving  business. 

A  table  with  a  wreath  of  flowers  of  extremely  compli- 
cated pattern,  and  admirably  finished,  with  a  vast  number 
of  detached  marbles,  of  Derbyshire  work,  owned  by  Mr. 
Yallance,  attracted  general  attention  at  the  "London  Exhi- 
bition. Although  not  to  be  compared  with  the  Florentine 
work,  there  were,  nevertheless,  much  skill  and  labor  be- 
stowed upon  it. 

A  number  of  other  tables  of  inlaid  work,  of  the  cinque- 
cento  style,  were  likewise  weh1  executed.  The  exhibition 
of  Derbyshire  inlaid  work  was  very  large. 

A  mosaic  chess-table  from  the  Isle  of  Man ;  from  Lisbon, 
interesting  specimens  of  mosaic,  composed  of  sixty  speci- 
mens of  Portuguese  marbles ;  and  from  the  Cape  of  Good 
Hope,  a  peculiar  kind  of  inlaid  marble  work,  were  at  the 
London  Exhibition,  and  all  more  or  less  interesting. 


Clay  and  Porcelain  Mosaics* 

The  encaustic  and  mosaic  tiles  used  by  the  ancients  for 
ornamenting  houses,  for  pavements  and  walls,  have  of  late 
years  been  extremely  well  imitated,  both  in  England  and 
the  United  States. 

The  encaustic  or  inlaid  tiles  are  made  by  pressing  clay  in 
in 


434  A   POPULAR   TREATISE   ON   GEMS. 

the  plastic  state  into  an  embossed  plaster  mould,  the  pattern 
or  design  on  the  mould  being  raised.  When  the  tile  is 
withdrawn  from  the  mould,  the  outline  of  the  pattern  is 
indented,  and  the  indented  parts  are  filled  in  with  colored 
liquid  clays,  according  to  the  colors  it  is  desirable  to  pro- 
duce. The  surface  is  then  scraped  quite  flat,  until  the  pat- 
tern appears  well  defined.  The  tile  is  then  heated,  or  as  it 
is  termed,  fired,  which  brings  out  the  colors  to  the  proper 
tint. 

The  Venetian  tiles  and  mosaics  are  produced  by  the  com 
pression  of  powdered  clays  into  metal  dies,  of  any  geometri- 
cal form  that  may  be  devised,  the  clays  having  been  previ- 
ously stained  with  metallic  colors.  -  Each  tile  or  tessera  is, 
of  course,  of  the  same  color  throughout.  When  fired, 
they  are  arranged  on  a  smooth  platform,  with  the  faces 
downward,  according  to  the  design  intended,  after  which 
liquid  Roman  or  Portland  cement  is  poured  upon  them, 
and  they  are  thus  formed  into  slabs  of  any  size  required. 

The  Alhambra  or  Spanish  tiles  are  made  by  pressing 
plastic  clays  into  an  embossed  mould,  which  forms  grooves 
or  indentations ;  these  tiles  are  then  fired,  and  come  out  of 
the  oven  with  the  pattern  formed.  The  indentations  are 
then  filled  in  with  enamels  of  various  colors  and  fired  again, 
which  produces  a  brilliant  efiect,  and  renders  the  tiles  suit- 
able either  for  floors  or  the  interior  walls  of  buildings. 

A  mosaic  pavement,  composed  of  tesserce  of  vitrified  clay, 
of  several  colors  and  shapes,  all  produced  by  machinery 
with  great  rapidity,  and  without  the  necessity  of  chipping 
any  of  the  tesserce,  and  at  the  same  time  making  an  endless 
variety  of  patterns,  is  produced  in  England,  in  the  follow- 
ing manner :  The  clay  being  prepared  in  the  usual  way, 
by  washing  and  sifting,  and  stained  with  various  metallic 
oxides  (oxide  cobalt,  blue  smalts,  manganese,  zaffre,  red 
lead,  crocus  mart-is,  an  rum  musivum,  oxide  chrome,  copper 


MOSAIC   AND   PIETEA   DTJBA.  435 

scales,  &c.,  the  principal  ingredients  used),  is  formed  into 
thin  ribbons,  about  three  eighths  of  an  inch  thick  and  from 
three  to  four  feet  long,  by  a  machine ;  out  of  these  ribbons 
the  tessercB  are  cut  by  a  patented  machine,  with  great  ra- 
pidity, and  when  dry  are  baked  in  saggers  in  the  usual 
way. 

Pavement  slabs  are  made  by  laying  these  tesserae  face 
downwards  on  a  perfectly  flat  slate,  the  pattern,  of  course, 
being  reversed,  and  covering  their  backs  with  a  layer  of 
Portland  cement,  and  two  layers  of  rough  thin  tiles,  care- 
fully embedded  in  the  cement.  In  this  way  strong  slabs  are 
formed,  of  from  an  inch  and  three  quarters  to  two  inches 
thick,  which  are  almost  perfectly  impervious  to  moisture  or 
rising  damp. 

The  capitol  extension,  in  the  City  of  Washington,  United 
States,  is  embellished  with  encaustic  tiles ;  and  both  the 
pavement  in  the  halls  of  the  house  of  representatives  and 
senate  chamber,  and  the  avenues  leading  to  them,  and  the 
encased  walls,  are  laid  out  with  bright-colored  tiles,  in  the 
most  gorgeous  manner. 

Mosaic  Tiles  made  with  Soluble  Glass. 

The  many  useful  applications  of  soluble  glass  (which 
may  be  the  silicate  of  soda,  or  the  silicate  of  potash,  or 
both  alkalies  combined  with  the  silica),  form  a  new  era 
in  the  production  of  an  artificial  stone,  which,  if  properly 
adapted,  must  ultimately  supersede  all  other  artificial 
stones  or  cements  of  any  kind.  If  grains  of  sand,  pebbles, 
lime,  marble,  or  even  granite,  clay,  and  fluor-spar,  are 
mixed  with  soluble  glass  into  a  paste  of  the  consistency  of 
putty,  and  this  paste  is  then  moulded  into  any  required 
form,  after  slowly  air-drying  and  burning  the  articles  thus 
manufactured  in  a  kiln  at  a  bright-red  heat,  which  may  be 


436  A  POPULAR  TREATISE  ON  GEMS. 

maintained  for  any  length  of  time,  by  which  process  the 
alkali  contained  in  the  soluble  glass  is  set  free,  the  silica 
combines  with  the  lime,  and  more  particularly  with  the 
fluor-spar  (fluoride  of  calcium),  so  durable  a  cement  is 
formed  thereby,  that  it  will  not  admit  of  the  smallest 
absorption  of  moisture,  and  consequently  is  absolutely  un- 
attackable  by  frost.  By  applying  the  chloride  of  calcium 
in  solution  to  the  cement,  the  supposed  objection  that  the 
salts  of  soda,  or  alkali,  are  efflorescing  by  degrees,  is  hereby 
obviated,  for  the  chloride  of  calcium  at  once  absorbs  the 
alkali. 

Soluble  glass  may  be  colored  by  various  metallic  oxides, 
so  as  to  produce,  when  heated,  very  sharp  colors,  similar  to 
enamels,  and  may  also  be  employed  for  a  coating  over 
other  paints,  such  as  fresco,  &c. 

As  a  cement  for  joining  together  heterogeneous  and  ho- 
mogeneous substances,  it  is  unsurpassed,  and  when  applied, 
renders  the  substances  so  coated  both  water  and  fire  proof. 

If  soluble  glass  is  intended  for  a  varnish,  the  proper  spe- 
cific gravity  is  1'165,  but  for  a  paint  it  may  be  reduced  to 
that  of  water. 

In  France,  soluble  glass  is  much  used  in  coating  com- 
mon building-stones,  for  the  purpose  of  rendering  them 
damp-proof.  Marble  buildings  and  damp  cellars  may  be 
made  impervious  to  dampness  by  varnishing  the  surface 
with  soluble  glass ;  although  the  proper  mode  is  to  exhaust 
the  air  from  the  stone  or  brick,  and  then  impregnate,  it 
with  soluble  glass  by  pressure.  A  patent  was  lately  taken 
out  in  England,  for  preserving  building,  pier,  and  wharf 
stones,  by  first  coating  them  with  a  wash  of  chloride  of  cal- 
cium, and  afterwards  by  the  application  of  the  concentrated 
solution  of  soluble  glass, — repeating  the  operation  several 
times.  Soluble  glass  was  introduced  into  the  United 
States,  by  the  author  of  this  work,  in  the  year  1831,  under 


MOSAIC   AND   PIETEA   DURA.  43} 

the  authority  of  the  government,  for  the  purpose  of  pro- 
tecting the  cannon  and  balls,  exposed  to  the  weather  in 
the  Brooklyn  Navy  Yard,  against  rust ;  for  this  purpose, 
when  treated  with  the  various  coloring  pigments, — such  as 
oxide  of  manganese,  umber,  terra  di  sienna,  ochre,  Venetian 
red,  ultramarine,  &c., — it  is  admirably  adapted. 


Q 


Diamond 


••• 

Oriental        OK  •"/:  Or. 

Topaz,    -ItnetfiYst     Jlnbv     Ckrvsoberfl 


Chrsobtil 


a  a 


-  tiarnet  ~~  -  Cinnninfini 


C     1[H 


•••' 


Blood 


-Jaspe 


Chciti-edonv 


(Itrxopnise  ftridffte      Chwsolite  Opal 

1 


tus(.         Lapis 
stoiie       Lazuli          TuriputHSf  Malachite  Amber 

mrnam    tmwm        — i    IgM 
, 1     HHHI 


/>A.-,,y,x,«       /,dTO  ^c         Ltpidatitv     .Varityan    Serpentine  Hoc/use    Labnada 


Vurblt 


Granite 


Porphrrr 

a  E 


EXPLANATION  OF  PLATES. 


PLATE    II. 


THE   MOST   REMAKKABLE   EOTJGH   DIAMONDS. 

No.  1.— The  Nizam,  from  India;  it  weighs  340  carats,  is  valued 
at  five  millions  of  francs,  and  belongs  to  the  King  of  Golconda. 

No.  2. — The  great  rough  Diamond,  as  described  by  Tavernier, 
from  India,  weighing  282£  carats. 

No.  3. — The  great  South  Star,  from  Brazil,  weight  when  rough 
254i  carats,  was  found  in  the  mines  of  Begagem,  in  the  province 
of  Minas  Geraes,  in  Brazil.  It  is  as  clear  as  water,  slightly  tinged 
with  yellow ;  it  is  valued  at  two  and  a  half  millions  of  francs ;  it 
is  thirty  millimetres  in  height,  forty  in  length,  and  twenty-seven 
in  breadth.  Its  shape  is  a  twelve-faced  rhomboid,  presenting 
altogether  twenty-four  triangles. 


DIAMOND    LATHE. 


PL.2. 


-<^  ^. 


fTfFjn 


PL. 3 


THE.    LARGE  ROUGH  DIAMONDS. 


PLATE   III. 


KEMABXABLE  BOUGH  DIAMONDS. 

No.  4. — The  great  Spheroidal,  six-sided,  with  forty-eight  facets. 
"    5. — The  spheroidal  Diamond,  with  twenty-four  facets. 
"    6. — A  dodecahedral-pentagonal  rough  Diamond. 
"    V. — A  dodecahedral-rhomboidal  rough  Diamond. 
"    8. — An  Octahedron,  with  twenty-four  facets. 
"    9. — An  Octahedron,  the  primary  form. 


PLATE   IY. 


REMAKKABLE  BOUGH  DIAMONDS. 

0i  10. — A  rough  Brazilian  Diamond. 

"  12. — A  regular  Tetrahedron. 

"  12. — A  round,  concretional,  rough  Diamond,  called  Boort, 

"  13. — A  rough  Brazilian  Diamond. 

"  14. — A  rough  cubical  Diamond. 

"  15. — A  rough  Brazilian  Diamond. 

"  16. — A  truncated  octahedron  Diamond. 

«  17.— A  rough  Diamond,  described  by  Ta vernier. 

"  is. — A  triangular  crystal  of  Brazilian  Diamond. 

"  19. — An  Octahedron,  with  modified  secondary  form. 


PL.  4 


ROUOH     O/ AM  ON  OS 


IUIIFBESI 


ROUGH      DIAMONDS 


PL.  6. 


PLATE  Y. 


No.  1. — The  improved  Diamond  Lathe  (exhibited  in  the  Paris 
Exhibition,  1855,  by  Phillippe). 
No.  2  and  2  a. — The  pincers,  front  and  side  view. 

THE  PBINCIPLE  OF  CUTTING. 

No.  3. — a.  The  table  of  a  brilliant.  &.  The  triangular  faces. 
c.  The  angles  terminating  into  planes,  d.  Lozenges — 4  large  and 
4  small,  e.  The  planes  on  the  edge  of  the  stone. 

No.  3  a.—f.  The  angles  parallel  with  the  planes,  g.  Pavilion 
or  facets  corresponding  to  Lozenges.*  h.  The  collet  of  the  bril- 
liant. 

No.  4. — A  rough  Diamond,  cleansed. 
"    5. — Cut  of  the  crown. 

"    5  a.— The  three  different  cuts.  a.  The  table.  5.  The  girdle. 
c.  The  collet. 

No.  6.— A  Brilliant  not  recut. 
"    7.— A  Brilliant  recut. 
«    8. — Hose  Diamond,    a.  The  crown.    5.  The  facets. 

*  Lozenge  is  the  geometrical  form  of  a  rhomb. 


PLATE  VI. 


THE  MOST   CELEBRATED   OUT  DIAMONDS. 

No.  1. — The  Grand  Mogul;  it  weighs  279  carats,  and  is  valued 
at  twelve  millions  of  francs. 

No.  2. — The  Orlow,  the  great  Russian  Diamond,  weighs  195 
carats,  and  is  the  size  of  a  pigeon's  egg :  cost  two  millions  of  francs 
and  a  pension  of  one  hundred  thousand  francs.* 

No.  3. — The  table  Diamond  of  Ta vernier,  weighing  242£  carats. 
"    4. — The  Polar  Star,  weighing  40  carats. 
"    5. — The  Shah,  belonging  to  the  Russian  crown,  weighing 
95  carats. 


*  It  is  on  the  top  of  the  Russian  sceptre,  and  has  the  form  of  a  knob  of  a  cane ;  the 
under  surface  is  a  plane. 


THE  MOST  CELEBRATED   CUT  DIAMONDS . 


PL.  6. 


%> 

tnn 


B 


PL.T. 


THE.  MOST  CELEBRATED  CUT  DIAMONDS 

6  7 


PLATE  VII. 


THE  OELKBEATED  OUT  DIAMONDS. 

No.  6.— The  Nassack,  weighs  78|  carats;  was  sold,  in  1839,  foi 
seven  thousand  six  hundred  pounds  sterling,  to  the  Marquis  ol 
Westminster. 

No.  7. — The  great  India  half-cut  Diamond,  weighing  112£ 
carats. 

No.  8. — A  brillianted  Rose  in  pear-shape,  from  India,  weighing 
16  carats. 

No.  9. — Another  Rose  in  pear-shape,  weighing  94^  carats. 

No.  10. — A  recut  India  Brilliant,  weighing  29  carats. 

No.  11  and  11  a.— The  South  Star  of  Halphen,  weighing  124 
carats. 

No.  12  and  12  a. — The  Regent,  or  Pitt ;  it  weighs  136  carats, 
belongs  to  the  French  crown,  is  valued  at  five  millions  of  francs, 
and  is  certainly  the  best-proportioned  Diamond  in  the  world ;  it 
is  perfectly  pure  and  transparent,  and  sparkles  with  a  magnificent 
play  of  color. 


PLATE  Till. 


THB   CELEBRATED   OUT   DIAMONDS. 

No.  13. — The  Piggot,  belonging  to  England,  weighs  82  carats. 

No.  14. — The  Pacha  of  Egypt's  Diamond,  weighs  49  carats. 

No.  15. — The  Koh-i-noor,  as  it  came  from  India  ;  and  15  a,  its 
present  form,  from  a  side  view. 

No.  16. — An  India  pear-shaped  Brilliant,  weighing  31 1  carats. 

No.  17. — A  Half-Brilliant,  faceted,  weighing  14J  carats. 

N"o.  18. — Large  Rose  Diamond,  of  280  carats. 

No.  19. — An  irregular  Rose  Piamond,  in  pear  form,  weighing 
20  carats. 

No.  20, — An  India  Brilliant,  described  by  Tavernier,  weighing 
52  carats. 

No.  21  and  21  a. — Large  table  Diamonds,  step-cut. 


THE.   MOST  CELEBRATED  CUT    DIAMONDS.  PL.  8. 


^ 


; 


THE.  MOST  CELEBRATED  CUT  DIAMONDS  . 
22 


PL. 9. 


PLATE   IX. 


THE  OELEBBATED  OUT  DIAMONDS. 

No.  22. — The  great  Austrian  Brilliant,  belonging  to  the  Grand 
Duke  of  Tuscany,  weighing  139£  carats ;  valued  at  seven  millions 
of  dollars. 

No.  23. — The  Eugenie  Diamond,  belonging  to  the  Empress  ol 
France,  weighing  51  carats. 

No.  24. — The  Hope  Diamond,  a  beautiful  blue  Diamond,  weigh- 
ing 44i  carats. 

No.  25.— A  Brillolet  of  16£  carats. 

No.  26. — A  knob-shape  of  10  carats. 

No.  27. — A  table-shape  of  10  carats. 

No.  28.— A  flat  Diamond  of  20  carats. 

No.  29.— A  flat  Diamond  of  14  carats. 

No.  30  and  30  a. — The  celebrated  Sancy,  belonging  to  the 
French  crown-jewels,  weighing  33£  carats,  of  pear-shape ;  is 
valued  at  one  million  francs. 

No.  31. — A  large  cleaved  Diamond,  of  64  carats,  from  India. 


PLATE    X. 


Ko.  1.—  Rock-Crystal  Group,  from  Arkansas,  IT.  S. 
Size  and  weight  of  Diamonds,  both  round  and  square,  from  that 
of  half  a  carat  to  18^  carats. 


PL.X. 


PL.X/. 


PLATE   XI. 


AMEBICAN 


No.  1.  —  California  Marble. 

u  2.  —  Verde  Antique,  from  Vermont. 

»  3.—  Shell  Marble,  from  New  York. 

"  4.  —  Tennessee  Marble. 

"  5.  —  Bale's  Breccia  Marble,  from  Lancaster,  Pa. 

"  6.—  Potomac  Marble. 

"  7.—  Variegated  Marble,  from  the  State  of  New  York. 


PLATE    XII. 


No.  1. — Black  Marble,  with  petrified  volutes  (Pyramidella  tur 
Unella). 

No.  2. — Red,  green,  and  white  brecciated  Marble,  from  Sicily. 

No.  3. — Red  mottled  Marble,  tertiary  fresh-water  Limestone, 
from  Swabian  Alps,  cut  parallel  to  the  planes  of  the  layers. 

No.  4. — Pale,  yellow,  and  violet  Marble,  from  the  Jura,  in 
Wiirtemberg. 

No.  5. — Reddish-yellow  and  bluish-red  mottled  Marble,  from 
Wiirtemberg. 

No.  6. — Marble,  tertiary,  cut  perpendicularly  to  the  planes  oi 
the  layers,  from  the  Alps. 

No.  7. — Pale-yellow  Marble,  and  violet  Flakes,  from  Wiirtem 
berg. 


PL.XI/. 


PLJfM. 


PLATE    XIII. 


No.  1. — Tertiary  brecciated  Marble,  from  the  Pyrenees. 

No.  2. — Red  Granite,  consisting  of  red  felspar,  grey  quartz,  anc 
black  mica,  from  Upper  Egypt ;  used  by  the  ancient  Egyptians  ir 
their  monuments. 

No.  3. — Fibrous  Calcite,  or  so-called  Thermal  Tufa,  Sprude1 
stein,  from  Carlsbad. 

No.  4. — Compact  Brown-spar,  from  Gibraltar. 

No.  6. — Agate  Marble,  from  Algiers. 


PLATE   XIY. 


No.  1.— Kyanite,  light-blue  and  oblique  rhombic  prism,  with 
truncation,  from  St.  Gothard. 

No.  2. — Amphibole  or  dark-green  Hornblende,  Actinolite,  an 
oblique  rhombic  prism,  from  Tyrol. 

No.  3. — Precious  Serpentine,  in  right  rectangular  prisms,  from 
Norway. 

No.  4. — Lumachelli  or  Fire  Marble,  containing  fossil  shells;  the 
variegated  colors  are  owing  to  nautilus  or  ammonite,  from 
Corinthia. 

No.  5. — Ruin  Marble,  cut  perpendicularly  to  the  planes  of  the 
layers,  from  Tuscany. 

-$o,  g. — Pea-stone,  calcareous  Stalactite,  from  the  hot  springs 
of  Carlsbad. 

No.  7. — Dark-brown  ribbon  Agate,  Arabian  Onyx,  from  the 
East  Indies. 

No.  8. — Pale-yellow  Marble,  from  Florence. 

No.  9. — Variegated  Marble,  containing  Corals,  from  the  transi- 
tion rocks  of  Nassau. 

No.  10.— Bed  brecciated  Marble,  from  Italy. 

No.  11. — Black  Porphyry,  from  Sweden. 


PLJ(/V. 


PL.  XV. 


PLATE    XY. 


No.  1. — Egyptian  Jasper. 

No.  2. — Ribbon  Jasper,  striated  with  red  and  green,  froir 
Siberia. 

No.  3. — Pudding-stone  or  Quartz  Conglomerate,  from  Scotland. 

No.  4. — Horny-colored  Agate,  from  the  East  Indies. 

No.  5. — Chrysolite,  from  the  East  Indies. 

No.  6. — Noble  Garnet,  Pyrope,  from  Bohemia. 

No.  7. — Dark-yellow  Topaz,  burnt,  and  called  Balais,  from 
Brazil. 

No.  8. — Granite,  from  Milan. 

No.  9.— Wood  Opal,  a  petrified  pine,  from  Hungary. 

No.  10. — Black  ribbon  Agate,  from  the  East  Indies. 

No.  11. — Green  Tourmaline  (Brazilian  Emerald)  in  Dolomite, 
from  St.  Gothard. 

No.  12. — Moss  Agate  or  Mocca-stone,  from  the  East  Indies. 

No.  13.— Dark  Topaz,  from  Brazil. 


PLATE    XVI. 


No.  1. — Black  and  white  mottled  Marble,  from  the  monotniE 
limestone  of  Ardennes. 

No.  2. — Red  antique  Porphyry,  from  Upper  Egypt. 

No.  3. — Blue  Copper,  Azurite,  from  Germany. 

No.  4. — Malachite,  Green  Copper,  from  Siberia. 

No.  5. — Natrolite  on  Clinkstone,  from  Bavaria. 

No.  6. — Clear-yellow  Amber,  inclosing  several  flies,  from  the 
coast  of  the  Baltic,  near  Dantzic. 


PL.W. 


PLXVII. 


PLATE    XVII. 


No.  1. — Dark-green  Serpentine,  from  the  Apennines. 

No.  2. — Amazon-stone  or  apple-green  Felspar,  an  obliqne  rhom 
bic  prism,  from  the  Ural  Mountains. 

No.  3. — Fortification  Agate,  from  Oberstein. 

No.  4. — Green  Porphyry  Felspar,  from  Greece. 

No.  5. — Serpentine,  Ophicalite,  or  Verde  de  Corsica  duro,  from 
Corsica. 

No.  6. — Labrador  Felspar,  from  Labrador. 


458 


INDEX. 


Borax,  double  refraction  of,  88;  reagent, 

116. 

Botryoidal,  72. 
Brachydiagonal,  46. 
Brachydomes,  47. 
Brachypyramids,  47. 
Brazil,  discovery  of  diamonds    in,  1ST; 

revenue  from  diamonds  in,  201. 
Brewsterline,  265. 
Brilliant,  the,  161. 
Brillionets,  161. 
Bromine,  119. 
Bronzite,  fusibility  of,  116. 
Brown  spar,  56. 
Burning  of  gems,  171. 

0. 

Cabochon  cut,  165. 

Cachelong,  an  opal,  807. 

Cadmium,  test  of;  125. 

Cairngourm  crystals,  261. 

Calamine,  55. 

Calc  spar,  43,  65,  66,  70,  73 ;  hardness,  78 ; 
double  refraction,  86;  varieties  of,  364. 

Calcareous  scheelite,  refraction  of,  88. 

Cameos,  shell,  425. 

Cannel  coal,  described,  354. 

Carat,  origin  of  the  word,  181 ;  weight  of 
four  grains,  ib. 

Carbon,  120. 

Carbonate  of  soda,  reagent,  116;  refraction 
of  carbonates,  87;  electricity,  99. 

Carbuncle  (see  Spinelle),  228 ;  garnet,  251. 

Carengeair's  goniometer,  5S. 

Cornelian,  hardness  of,  80;  described,  279. 

CatVeye  quartz,  described,  270. 

Caves,  list  of  American,  880. 

Cerium,  test  of,  127. 

Chabasite,  56,  65. 

Chalcedony,  73;  hardness  of,  SO;  refrac- 
tion of,  88 ;  described,  277.  Varieties— 1, 
Chalcedonyx;  2,  Mochastones;  3,  Kain- 
bow :  4,  Cloudy ;  5,  Plasma ;  6,  Semicar- 
nelian  or  ceregat ;  7,  Sappharine ;  8,  St 
Stephen's  stones,  278;  varieties  of,  77. 

Chalcopyrite,  64. 

Chalk,  365. 

Chemical  properties  of  minerals,  102 ;  reac- 
tion, 113. 

Chlorine,  119. 

Chlorophane  (a  fluor  spar),  335. 

Chromate  of  lead,  refraction  of,  87. 

Chromium,  test  of,  127. 

Chrysoberyl,  degree  of  hardness,  80 ;  real 
gem,  136;  same  as  cyinophane,  225. 


Chrysolite  (Peridote,  olivin),  nardness  ot, 
80 ;  real  gem,  136 ;  oriental,  a  sapphire, 
216;  refraction  of,  87;  Ceylon,  a  tourma- 
line, 256;  described,  294. 

Chrysoprase,  described,  292 ;  value,  294. 

Cinnabar,  refraction  of,  88. 
innamon  stone  or  Essonite,  253 ;  see  Hya- 
cinth de  Ceylon. 

Cleaning  gems,  172. 

Cleavage,  varieties  of;  76. 

Clinopinacoids,  51. 

Clinoprisms,  51. 

Clinopyramids,  51. 

Coal,  354 ;  American  coal-fields,  ib. 

Cobalt,  solution  of,  reagent,  117;  test  of, 
125. 

Cobaltine,  80,  31. 

Collet  the,  explained,  161. 

Colophonite,  a  garnet,  249. 

Color,  change  of,  93;  table  of  colors  of 
minerals,  96 ;  of  gems,  136. 

Combinations,  81. 

Conazeranite  (felspar),  314. 

Copper,  test  of,  126. 

Coral,  described,  419 ;  varieties  of  red,  422. 

Cordierite,  a  real  gem,  136. 

Corundum,  hardness,  78 ;  refraction  of,  87 ; 
description  of,  214;  see  Sapphire. 

Corundum,  common,  or  Diamond  spar,  de- 
scribed, 223 ;  granular,  or  emery,  224. 

Crown-jewels  of  France,  value  of;  207. 

Crown-jewels  of  Queen  Victoria,  210. 

Cryptoiine,  265. 

Cryptocrystalline  minerals,  73. 

Crystalline,  19. 

Crystallized,  19. 

Crystals,  defined,  20 ;  described,  »&. ;  sys- 
tems of,  ib.  ;  imperfections  of,  54 ;  strise 
55 ;  drusy,  56 ;  measurement,  58 ;  macles 
or  tw4n  crystals,  61 ;  irregular  aggrega- 
tion, 70. 

Cyanite,  73 ;  described,  827. 

Cymophane  (oriental  chrysolites),  refrac- 
tion of,  87 ;  see  Chrysoberyl. 

D. 

Deltoid  dodecahedrons,  28;  sign,  80. 

Derivation  of  forms,  27.  • 

Diamond,  24,  25,  29;  hardness  of,  78,  80  i 
double  refraction  of,  87 ;  first  cut  by  Ca- 
radossa,  151 ;  manner  of  cutting,  156, 183 ; 
polishing,  158 ;  forms  of,  161 ;  discovery 
in  a  diamond  lens,  182 ;  general  account 
of,  183,  etc. ;  pure  carbon,  184;  artificial, 
ib. ;  form  of  crystals,  185 ;  color,  ib. ;  the 


INDEX. 


459 


compact,  ib. ;  the  original  bed  of,  187: 
loss  In  cutting,  193;  Hindoo  division  of. 
195;  value,  Vt.  ;  color,  purity,  ib.;  de- 
gree of  clearness,  ib. ;  cat  and  size,  196; 
prices  of,  197-8;  celebrated  diamonds, 
154, 193,  203 ;  the  largest  known,  208 ;  in 
Victoria's  crown,  211 ;  at  the  Industrial 
Exhibition,  212. 

Diamond  grinders,  155. 

Dimorphism,  110. 

Dioptase,  double  refraction  of,  88. 

Disthene  (Kyanite,  sappare),  described, 
321. 

Ditetragonal,  pyramids,  36. 

Divelsteene,  156. 

Dodecahedrons,  subdivided,  22. 

Dolomite,  double  refraction  of,  87. 

Double  facet  cut,  165. 

Doublets,  180. 

Druses,  71. 

Drusy  crystals,  56. 

Dyakisdodecahedron,  30;  sign,  31. 


E. 

Edingtonate,  double  refraction  of,  SS. 

Electricity  of  minerals,  99. 

Electro-chemical  elements,  table  of,  105. 

Electroscopes,  99. 

Elongated  brilliant  facet  cut,  165. 

Emerald,  hardness  of,  80;  double  refrac- 
tion, 85;  a  real  gem,  136;  the  oriental,  a 
sapphire,  216;  described,  235;  emerald 
proper,  ib.;  how  cut,  237;  value,  ib.; 
remarkable  emeralds,  238 ;  the  Duke  of 
Devonshire's,  239 ;  the  Brazilian,  a  tour- 
maline, 256. 

Emery,  a  common  corundum,  224. 

Engraving  on  gems,  167. 

Essonite,  or  cinnamon-stone ;  hardness  of, 
80;  real  gem,  136,  250;  described,  253. 

Euclase,  double  refraction  of,  87;  descrip- 
tion of,  234. 


F. 

Facets,  161. 

.Fablore,  63. 

Felspar,  52,  53,  75;  described,  312;  com- 
mon, 315;  ad ul aria.  312;  march isonite. 
814;  leclite  or  helleniaU,  conazeranite. 
ib.;  amazon-stone,  315;  porphyry,  391 ; 
sienete,  893. 

Fish-eye  (adularia),  31i 


Fluor  spar,  crystalline  forms,  23  24,  25,  56, 
63,  65, '70;  hardness,  78,  80;  ciouble  re- 
fraction of,  88;  electricity,  99;  describ- 
ed, 333. 

Fluorine,  test  for,  120. 

Foil,  use  of,  169. 

Form,  primary,  26 ;  semi-tesseral,  28 ;  par- 
allel semi-tesseral,  30. 

Forms  of  crystalline  aggregates,  71. 

Fortification  agate,  284. 

Fracture  surfaces,  78. 

Fusibility,  test  minerals  as  to,  115. 


G. 

Galena,  23,  24,  56,  63. 

Garlic,  used  in  repairing  gems,  170. 

Garnet,  23,  25,  27 ;  hardness  of,  80 ;  double 
refraction  of,  88 ;  magnetic,  100 ;  a  real 
gem,  136 ;  described,  247 ;  varieties,  24S ; 
Syrian,  Bohemian,  Ceylonian,  Aplome, 
ib.;  precious  or  almandine,  24S ;  coloph- 
onite,  249;  allochroite,  ib.;  grossular, 
250;  topazolite,  ib.;  melanite,  pyrena- 
ite,  ouwarowite,  ib.;  the  ancient  car- 
buncle, 251. 

Gems,  135;  enumerated,  136;  color,  grav- 
ity, and  hardness  of,  ib.;  chemical  char- 
acter, 139;  composition,  ib.;  artificial 
production,  140 ;  geological  character, 
145;  geographical  distribution,  140;  di- 
vision and  nomenclature,  147;  history 
of,  148;  superstitions  as  to,  149;  sculp- 
ture in,  151 ;  grinding,  153 ;  engraving, 
167;  sawing  and  drilling,  168  ;  polishing 
materials,  ib.;  heightening  color  of,  169 ; 
setting,  171;  cleaning  of,  172;  imita- 
tions,^.; 1,  pastes,  ib.;  2,  doublets,  ISO ; 
3,  burning,  180;  price  of,  181;  optical 
use  of,  181. 

Girasol  sapphire,  216 ;  fire  opal,  304 ;  adu- 
laria, 313. 

Girdle,  in  diamonds,  what?  161. 

Glucina,  test  of,  123. 

Goldstone,  a  paste,  278. 

Goniometers,  58. 

Goutte  de  sang,  a  spinelle,  228. 

Grand  mogul  diamond,  193,  203. 

Granite,  described,  896;  American  varie- 
ties, 397. 

Gray  copper  ore,  28,  68. 

Grossular  garnet,  250. 

Gypsum  crystals,  51,  56,  68,  74;  doable 
refraction  of,  88 ;  tntin  gypsum,  341 ;  al- 
abaster, ib. 


460 


INDEX 


H. 

Haematite,  65. 

Hardness  of  minerals,  78 ;  Mob's,  scale  of, 
ib.;  rough  scale,  79 ;  of  precious  stones, 
80  ;  of  gems,  136. 

Hatchet-stone  (jade),  361. 

Hausmanite,  64. 

Hauyne,  described,  822. 

Heliotrope,  described,  282. 

Hellefliata,  or  Leclite  (felspar),  314. 

Helvine,  28. 

Hemihedric  crystal,  21. 

Hetnimorphism,  54. 

Hemiorthotype  system,  21. 

Hexagonal  system,  21,  39;  pyramids  40; 
dihexagonal,  41 ;  rbombohedral,  42. 

Hexahedron,  22,  23 ;  sign  of,  27. 

Hexakisoctahedrons,  25 ;  sign  of,  27. 

Hexakistetrahedron,  28;  sign,  30. 

Holland  diamond,  206. 

Holobedric  crystals,  21,  22. 

Hope  diamond.  206. 

Hornblende,  68,  320. 

Hornstone,  described,  277. 

Hyacinth,  hardness  of,  80;  oriental,  a  sap- 
phire, 215;  a  variety  of  zircon,  246 ;  de- 
scribed, 247. 

Hyacinth  de  Ceylon  (Essonite,  or  cinna- 
inon-stone),  258. 

Hyaline,  19. 

Hydrate  of  magnesia,  double  refraction 
of,  88. 

Hydrometer,  81. 

Hydrophane,  a  variety  of  opal,  305 ;  curi- 
ous property,  ib. 

Hydroxide  of  iron,  double  refraction  of,  88. 

Hypersthene,  not  hornblende,  820;  de- 
scribed, ib. 


I. 


Iceland  spar,  66 ;  double  refraction  of,  86 ; 
described,.  364 

Icositetrahedrons,  22,  24 ;  sign  of,  27. 

Idocraso,  double  refraction  of,  88 ;  describ- 
ed, 321. 

Ignoble  metals,  101. 

Imitations  of  gems,  172. 

Indicolite  (Brazilian  sapphire),  256. 

Iodine,  test  for,  119. 

lolite,  real  gem,  136;  described,  297;  di- 
chroite;  peliom,  lynx  and  water  sapphire, 
298. 

Iridescence,  93. 


Iron,  double  refraction  of,    88;    test  olj 

127. 

Iron  pyrites,  30,  81,  55,  68. 
Irregular  aggregation,  70. 
Isomorphic  substances,  111. 
Isomorphism,  110. 
Itacolumite,  diamond-bearing  rock,  188. 


J. 

Jade  (nephrite,  hatchet-stone,  punamu), 
described,  361. 

Jargon  (see  Zircon),  244 ;  described,  246. 

Jaspachates,  a  variety  of  agate,  284 

Jasper  described,  273 ;  varieties :  1,  Egyp- 
tian ;  2,  Ribbon  spar,  276 ;  jasper  opal, 
308. 

Jet,  hardness  of,  80 ;  described,  353 ;  a  bi- 
tuminous coal,  ib. 

Jewish  tribes,  gems  allotted  to,  149. 

Jeweller's  wax,  172. 


K. 

Kaolin,  75. 

Kneeshaped  crystal,  64. 

Kohinoor,  a  celebrated  diamond,  154;  its 

loss  in  cutting,  193 ;  history  of,  208. 
Kuinur,  a  celebrated  diamond,  154. 
Kyanite  (sappare,  disthene)  described,  827. 


L. 

Labradorite,  70 ;  not  felspar,  317. 

Lamellar,  71. 

Lapidaries,  ancient,  151;  s6ciety  of,  153; 

gem  lapidary,  163;    common,  164;  his 

apparatus,  ib. 
Lapis  lazuli,  or  Armenian  stone,  described, 

322 ;  uses  of,  323. 
Lava  described,  360. 
Lava,  black  glass  lava,  or  obsidian,  310. 
Lazulite,  hardness  of,  80 ;  azure-stone,  324 ; 

used  to  imitate  lapis  lazuli,  ib. 

,  66  ;  test  of,  125. 
Leclite  (felspar),  314. 
Lepidolite,  described,  339. 
Leucite,  27. 
Lievrite,  48. 
Lithia,  test  of,  121. 
Lime,  test  of,  122. 
Lithographic  stone,  366. 
Love's  arrows,  a  rock  crystal,  261. 
Lustre,  93 ;  degrees  of,  94 ;  varieties  of,  ib 
Lyncurium,  not  tourmaline,  258. 


IND  EX. 


461 


M. 

Macles  or  twin  crystals,  61. 

Macrodiagonal,  46. 

Macrodoines,  48. 

Macropinacoid,  48. 

Macroprisms,  48. 

Magnetic  iron  ore,  24,  63. 

Malachite,  74;  hardness  of,  80;  describ- 
ed, 835;  beautiful  articles  made  of, 
338. 

Manganese,  test  of,  125. 

Marble  (Carbonate  of  lime),  described,  264; 
best  localities,  366 ;  ancient  marbles,  367 : 
French,  ib. ;  English,  863;  varieties  of 
Derbyshire,  ib. ;  marble  statuary,  370, 
876 ;  American  marbles,  871,  8S3 ;  white, 
ib. ;  ancrinital  or  bird's-eye,  372 ;  mar- 
bles, &c.,  in  N.  Y.  Geological  cabinet, 
373 ;  breccia,  375 ;  serpentine  or  verd  an- 
tique, ib.  ;  leocadia  breccia,  876 ;  Egyp- 
tian, 382;  Italian,  ib. ;  shell  marble, 
885. 

Marcasite,  66 ;  or  pyrites,  390. 

Marekanite,  brown  obsidian,  310. 

Measurement  of  crystals,  58. 

Meerschaum,  described,  857;  uses  of, 
358. 

Meionite,  double  refraction  of,  888. 

Melanite,  garnet,  250. 

Mellite,  double  refraction  of,  88. 

Mercury,  test  of,  124 

Mica,  double  refraction  of,  88 ;  described, 
889.  ' 

Microcosmic  salt,  reagent,  116. 

Mineralogy,  how  limited  in  this  work, 
16. 

Minerals,  forms  of,  19 ;  crystalline,  amor- 
phous, ib. ;  physical  properties,  75 ;  hard- 
ness and  tenacity,  73 ;  specific  gravity  of, 
SO;  optical  properties,  84;  double  re- 
fraction, 85;  polarization  of  light,  89; 
pleochroism,  92 ;  iridescence,  93 ;  lustre, 
ib.;  color,  95;  phosphorescence,  98; 
magnetism,  100 ;  smell,  taste,  touch,  101 ; 
chemical  properties,  102;  composition, 
ib. ;  influence  of  chemical  composition 
on  external  character,  109;  chemical  re- 
action, 113;  fusibility,  114-;  solubility, 
11T;  classification,  129 ;  orders  of,  134 

Mispickel,  66. 

Mix  facet  cut,  164 

Mocha  stones,  chalcedony,  278. 

Mobs;  his  system  of  crystallization,  21; 
scale  of  hardness,  73. 

Molybdite,  double  refraction  of,  88. 


Monoclinochedric  system,  21,  49  ;  its  forae, 

49;  combinations,  51. 
Months,  gems,  allotted  to,  149. 
Moonstone  (Adularia),  318.  * 
Moroxite,  an  oolite,  387. 
Mosaic,  426;  Roman,  427;  Florentine  or 

pietra  dura,  429;    clay    and   porcelain, 

433. 
Murchisonite  (felspar),  314' 


Nassak  diamond,  198;  its  value,  200,  204, 

210. 

Natrolite,  fusibility  of,  115;  described,  332. 
Naumann,  his  system  of  crystallization,  21. 
Nepheline,  double  refraction  of,  88. 
Nephrite  or  jade,  361. 
Nicholson's  hydrometer,  81. 
Nickel,  magnetism  of,  100;  test  of,  125. 
Nitric  acid,  test,  119. 
Nizam  diamond,  208. 
Noble  metals,  108. 
Non-metallic  elements,  113. 

o. 

Obsidian,  hardness  of,  80;  described,  809. 

Octahedron,  23;  primary  form,  26;  how 
distinguished,  ib. 

Ofigoclase,  69. 

Olivin,  or  Chrysolite,  294 

Ouwarowite,  garnet,  250. 

Onyx,  carnelian,  280  ;  agate,  288  ;  describ- 
ed, ib.  ;  cameos  of,  ib. 

Oolite,  a  calcareous  spar,  365,  836. 

Oolitic  crystals,  78. 

Opal,  73  ;  hardness,  80  ;  double  refraction, 
88  ;  iridescence,  93  ;  described,  299  ;  pre- 
cious opal,  ib.  ;  mother  of  opal,  801  ;  cel- 
ebrated specimens,  802;  fire  opal,  or 
girasol,  304  ;  common  opal,  805  ;  hydro- 
phanes,  ib.  ;  semi-opal,  806  ;  wood  opal, 
ib.  ;  cachelong,  807  ;  Jasper  opal,  808  ; 
Ceylon  or  water  opal,  ib. 

Orders  of  minerals,  137. 

Oriental  and  occidental  gems,  147.     .'  <^ 

Orlow  diamonds,  203. 

Orthopyramids,  51. 

Orthoprisms,  51. 

Orthopinacoids,  51. 

Orthotype  system,  21. 

Orthoclase,  52,  68;  fusibility,  115. 

Oxahverite,  double  refraction  of,  88. 

Oxide  of  tin,  double  refraction  of;  88, 

Oxidized  stones,  134 

Oxidized  ores,  134 


462 


I  N  DEX. 


P. 

Pastes  and  artificial  gems,  172 ;  receipts  fo 
colored,  176 ;  how  detected,  179. 

Paunched  diamonds,  195. 

Pavilion  facets,  162, 164 

Pearls  described,  400;  how  formed,  ib. 
localities,  401;  value  of,  407;  Unite 
States  pearls,  409 ;  artificial,  415. 

Peliom,  a  variety  of  iolite,  298. 

Pentagonal  dodecahedron,  30;  sign,  ib. 

Pentagonal  dodecahedron,  and  pentagona 

icositetrahedron,  not  observed  in  nature 

.     81. 

Peridote  (see  Sapphire,  Chrysolite),216, 294 
Phosphates  of  lead  and  lime,  double  re 

fraction  of,  88. 

Phosphate  of  lime,  388 ;  its  uses,  ib. 
Phosphorescence,  98. 
Phosphoric  acid,  test  of,  118. 
Phosphorite,  388. 

Pietra  dura  (Florentine  mosaic),  429. 
Piggot  diamond,  206. 
Pisolite  (calcareous  spar),  365,  386. 
Plasma,  chalcedony,  278. 
Plaster  of  Paris ;  a  gypsum,  342;  constitu- 
ents, ib. 

Platinum,  test  of,  126. 
Pleochroism,  92. 
Point  diamonds,  161. 
Polar-star  diamond,  206. 
Polarization  of  light,  89;  instrument  for 

observing,  90. 
Porodine,  19. 
Porphyry,  a  compact  felspar,  391 ;  Ameri- 
can varieties,  392. 
Potassa,  test  of,  121. 
Prase,  common  quartz,  described,  271. 
Prehnite,  56. 

Prismatic  topaz,  hardness,  78. 
Pseudomorphism,  74. 
Punamu  (jade),  361. 
Pyramidal  system,  21. 
Pyrenaite,  garnet,  250. 
Pyrites  described,  390;  also  called  Marca- 

site,  ib. 
Pyrope,  a  garnet,  248. 

Q. 

Quartz— cpmmon,  Eose  quartz,  cats-eye, 
prase,  avantnrine,  269. 

Quartz  crystals,  55, 56;  hardness,  78 ;  double 
refraction  of,  87,  88 ;  an  oxidized  stone, 
184;  a  gem^  136 ;  described,  259. 

Queen  Victoria's  crown,  210. 


R. 

Rainbow  chalcedony,  278. 
Bed  silver,  double  refraction,  88. 
Eefraction,  double,  85 ;  table  of,  87. 
Eegent  diamond,  154, 193,  204. 
Eeniform  crystals,  72. 
Ehombic  system,  21, 45. 
Ehombic  dodecahedron,  23 ;  sign  of,  27. 
Ebombohedral  system,  21. 
Ehombohedron,  42 ;  combinations,  44. 
Eibbon  spar,  276. 

Eock  of  Gibraltar,  carbonate  of  lime,  386 
Eock  crystal,  78;  hardness  of,  80;  de- 
scribed, 260;  varieties,  261;  specimens, 
262;  water  in  them,  265. 
Eock  salt,  hardness,  78;  double  refrac- 
tion, 88. 

Rose  diamond,  162. 
Rose  manganese,  described,  391. 
Rose  quartz,  269. 
Eubellite,  double   refraction,  88;  a  real 

gem,  136 ;  tourmaline,  255. 
Euby,  hardness  of,  80 ;  a  variety  of  sap- 
phire, 214,  215. 
Juby  cat's-eye,  216. 

Euby  spinelle,  almandine,   balais,  varie- 
ties of  spinelle,  227,  228. 
lussia,  discovery  of  diamonds  in,  189. 
~^util,  double  refraction  of,  88. 

s. 

Saline  ores,  134. 
aline  stones,  134. 
ancy  diamond,  204 ;  history  of,  ib. 

iappare  (kyanite,  disthene),  described,  327. 
appharine,  a  chalcedony,  278. 

sapphire,  hardness  of,  80 ;  iridescence  of, 
93 ;  real  gem,  136 ;  synonymous  with 
corundum,  214 ;  description  of,  ib.;  va- 
rieties, 215;  ruby,  oriental  hyacinth, 
amethyst,  sapphire,  and  topaz,  215; 
aquamarine,  chrysolite,  and  emerald, 
216;  its  constituents,  216;  locality,  217; 
mode  of  cutting,  ib.;  uses,  219 ;  value, 
ib. ;  remarkable  sapphires,  221,  222 ; 
Brazilian  sapphire  or  indicolite,  a  tour- 
maline, 256 ;  lynx  and  water  sapphire, 
iolites,  298. 

arda,  ancient  name  for  Carnelian,  279. 

ardonyx,  a  carnelian,  280;  agate,  289' 
cameos  and  intaglios,  290. 

atin  gypsum,  described,  341. 

atin  spar,  described,  340. 

calenohedron,  43. 


INDEX. 


463 


Scapolite,  79. 

Schlaggenwald  fluor  spar,  70. 

Schorl,  electric,  a  tourmaline,  256;  origin 
of  the  name,  258. 

Sculptors  in  gems,  152. 

Selenium,  test  for,  118. 

Semi-camel ian,  278 ;  a  chalcedony,  1b. 

Semi-tesseral  forms,  28. 

Serpentine,  described,  362. 

Setting  of  gems,  171. 

Shah  diamond,  206. 

Shrugging  in  diamonds,  195. 

Siberite,  a  tourmaline,  255. 

Siderite,  56. 

Sienite  (felspar  and  hornblende),  893; 
American  varieties,  894. 

Signs,  crystallographic,  27. 

Silver,  test  of,  126. 

Soda,  test  of,  121. 

Solubility,  .17 

Soluble  glass,  435. 

Somerviilite,  double  retraction  of,  88. 

South  star  diamond,  193,  210. 

Specific  gravity  of  minerals,  80 ;  how  as- 
certained, ib,;  of  gems,  136. 

Spinel,  spinelle,  23,  63;  hardness,  80; 
double  refraction,  87;  real  gem,  136; 
described,  227;  constituents,  ib.;  varie 
ties,  227,  223;  ruby  spinelle,  ruby  balais, 
almandine  ruby,  goutte  de  sang,  ib.;  im- 
itation, 229. 

Stalactite,  73, '365;  described,  380. 

Stalagmite,  73 ;  described,  380. 

Star  facets,  162. 

Star  of  the  south,  210. 

Staurolite,  66. 

Stephanite,  66. 

Stilbite,  48,  56. 

Strahlstein,  fusibility  of,  115. 

Striae,  55. 

Strontia,  test  of,  122. 

St  Stephen's  stone  (chalcedony),  278. 

Stygmite,  a  carnelian,  281. 

Sulphate  of  baryta,  87. 

Sulphur,  48;  refraction  of,  fc7 ;  test  for,  118. 

Sunstone,  sapphire,  216;  iridescence  of, 
93;  adnlaria,  313. 

Systems  of  crystals,  21. 


T. 

Table  of  a  diamond,  161. 
Table  diamond,  163. 
Talc,  hardness  of,  IS. 
Tantalium,  test  ot,  128. 


Tchingtching  (lapis  lazuli).  325. 

Tellurium,  test  ot,  124. 

Tenacity  of  minerals,  80. 

Terminology,  19. 

Tesseral,  or  tessular  system,  21 ;  described, 
82. 

Tetragonal  system,  21,  34;  closed  forms, 
35 ;  tetragonal  pyramids,  ib.;  ditetrago- 
nal,  ib.;  tetragonal  sphenoids,  36;  tet- 
ragonal scalenohedrons,  ib.;  open  forms, 
86 ;  tetragonal  prisms,  ib. 

Tetragonal  crystals,  how  distinguished,  87. 

Tetrahedral  form,  28 ;  its  sign,  29. 

Tetrakishexahedrons,  24 ;  sign  ot,  27. 

Thorina,  test  of,  123. 

Thumerstone,  or  axinite,  31L 

Tin,  test  of,  125 ;  tin  ore,  64. 

Titanium,  test  of,  129. 

Topaz,  crystal,  48;  hardness,  80;  optical 
power,  87;  electric,  99;  a  real  gem, 
136;  description  of,  229;  varieties,  230 ; 
cutting  of,  231;  localities,  232;  imita- 
tions, 233;  engraved  topazes,  ib.;  topaz 
of  the  ancients,  229,  234. 

Topazolite,  250. 

Tourmaline,  55,  56;  double  refraction  oft 
88;  polarization  of  light,  89;  real  gem, 
136;  described,-  254;  composition  of, 
255;  1.  Siberian  (siberite,  rubellite,  apy- 
rite),  ib.;  2.  Indicolite  (Brazilian  sap- 
phire); S.Brazilian  (emerald);  4.  Ceylon 
(chrysolite) ;  5.  Electric  schorl,  256 ;  lo- 
calities, ib.;  fine, specimens,  ib.;  not  lyn- 
curium  of  the  ancients,  258. 

Triakisoctahedron,  sign  o^  27. 

Triclinohedrie  system,  21,  52;  pyramids, 
53 ;  combinations,  ib. 

Trigonal  dodecahedrons,  28 ;  sign,  29. 

Tufa,  calcareous  spar,  365. 

Tungsten,  test  of,  128;  see  Wolfram. 

Turquoise,  hardness  of,  80 ;  described,  329  ; 
1.  true  oriental;  2.  bone,  or  occiden- 
tal, 330. 


u. 

Ultramarine,  made  from  lapis  lazuli,  324; 

how  prepared,  325;  imitations,  826. 
Uranium,  test  ot;  128. 

Y. 

Vanadium,  test  of,  128. 
Variolite  (felspar),  814. 
Venus'  hair,  261. 
Volcanic  glass,  or  obsidian,  80fc 


4G4 


INDEX. 


W. 

Water  in  rock  crystal,  analysis  of,  265. 
Weiss  and  Rose,  system  of  crystalliza- 
tion, 21. 

Wernerite,  double  refraction  o£  88. 
Wolfram,  68;  test  of,  120;  see  Tungsten. 
Wollaston's  goniometer,  58. 
uroodstone,  2TT. 


Yttria,  test  of,  128. 

z. 

Zinc,  blend,  64 ;  test  of  124. 

Zircon,  double  refraction  of,  87;  test  of 

123;  described,  244;  same  as  hyacinth 

ib.;  varieties,  245. 
Zuisang  (lapis  lasuli),  825. 


APPENDIX. 


CHRONOLOGICAL    LIST 


OF 


WORKS  ON  GEMS  AND  MINERALS 

• 

SINCE   THE   FIFTEENTH   CENTUBY. 


BECHAI,  (Ben  Ascliar,)  Biur  al  Hattorah,  (Exposition  of  the  Law  of 

Moses,)  a  Commentary  on   Exodus  xxviii.  17-20*   A.  M.  5207, 

(A.  D.  1447.*) 

Plinii  secundi,  (Caii,)  Naturalis  Historia.    Fol.     Venice,  1469. 
Aristotle,  Lapidarius,  de  novo  e  Graeco  translatus.    Lucas  Brandis. 

4to.    Eegia  Mer&ourg,  1473. 
Serapion,  (John,)  De  Medicamentis  tarn  simplicibus  quam  compositis. 

Mediolanum,  1473. 
Alberti,  (Magni,)  Philosophorum  maximi  de  Mineralibus.    Libri  V. 

Patavii,  1476. 
Avicenna,    (Abou-Ali-Alhussein-Ben-Adloulah,)  Canones  Medicinae, 

Latt.  reddit.     Venice,  1483. 

Csesalpinus,  (Andreas,)  De  Metallicjs  Libri  tres.    4to.    Rom.  1496. 
Leonardus,  (Camillus,  M.  D.,)  Speculum  Lapidum.     4to.      Venet. 

1502. 


*  This  work  contains  an  ample  account  of  the  properties  of  precious  stones. 
The  edition  of  1447  is  the  earliest,  but  it  has  since  been  many  times  re- 
printed. 


466  APPENDIX. 

Aben  Ezra,  (Rabbi,)  Commentarium  in  Decalogum.    8vp.    Hehr. 

Basel,  1527. 
Rue,  (Franc,  de  la,)  De  Gemmis.    8vo.    Parisii,  1547  ;  8vo.  Lugd. 

1622 ;  12mo.  Franc.  1626 ;  12mo.  Gron.  1626. 
Agricola,  (G.,)  De  Re  Metallica,  Libri  XI. ;  et  de  Natura  fossijium, 

Libri  X.    Fol.    BasUice,  1546. 
Ruens,  (F.,)  De  Gemmis  aliquot,  iis  prsesertim  quarum  Divus  Joannes 

Apostolus  in  sua  Apocalypsi  notavit.    8vo.    Paris,  1547. 
Libravii  (Andr.,)  Singularium  libr.  IV.  quorum  I.  et  III.  de  metallis 

lapidibus,  et  fossilibus.    8vo.    Franco/.  1549  ;  also  in  1601. 
Encelius,  (Christoph,)  De  Re  Metallica,  hoc  est,  de  origine,  varietate 

et  natura  corporum  metallicorum,  Lapidum,  Geinmarum  atque 

aliarum  quae  ex  fodinis  eruuntur  Libri  III.    8vo.    Francf.  1551. 
Theophrasti,  (Eresii,)  Opera  omnia,  Greece,  cura  Camotii  edidit  F. 

Turisanus.    §70.     Venetus,  apud  Aldi  filios,  1552. 
Langius,  (Johannes,)  Epistolse  Medicinales.    Fol.    Lugd.  1557. 
Agricola,  (George,)  De  Ortu  et  Causis  Subterraneorum.     De  Natura 

eorum  quse  effluunt  ex  Terra.    Fol.    Bas.  1558. 
Mandeville,  (John,)  Le  Grand  Lapidaire,  ou  sont  declarez  les  noms 

de  Pierres  orientales,  avec  les  Vertus  et  Proprietes  d'icelles,  et  iles 

et  pays  ou  elles  croissent.     12mo.    Paris,  1561. 
Porta,  (Giov.  Baptista,)  Magiae  Naturalis  Libri  IV.    Antwerp,  1561. 
Fallopius,  (G.,)  De  Medicatis  Aquis  atque  de  Fossilibus,  tractatus  ab 

Andrea  Marcolino  collectus.    4to.     Venitia,  *1564. 
Dolce,  (Ludovico,)  Libri  tre,  nei  quali  si  tratta  delle  diverse  sorti 

delle  Gemme  che  produce  la  Natura.    8vo.     Yen.  1564. 
Rulandus,  (Martinus,)  Medicina  Practica,    12mo.    Arg.  1564. 
Gesneri,  (C.,)  De  omni  rerum  fossilium  genere,  gemmis  lapidibus, 

metallis,  &c.    8vo.     Tiguri,  1565. 

Leonardus,  (Camillus;)  Trattato  delle  Gemme  che  produce  la  Natu- 
ra ;  traduzione  di  M.  Ludovico  Dobe.    8vo.     1565. 
Gesner,  (Conrad,)  Liber  de  Rerum  fossilium,  Lapidum,  et  Gem- 

marum,  maxime  figuris,  etc.    8vo.     Tig.  1565. 
Epiphanius,  De  duodecim  Gemmis  in  Veste  Aaronis.  Gr.  Lat.  cum 

corollario  Gesneri.    8vo.     Tig.  1565. 
Fabricius,  (G.,)  De  metallicis  rebus  et  nominibus  obs.  var.  erud 

quibus.  ea  potissimum  explicantur  quse  G.  Agricola  praeteriit.   8vo. 

Tiguri,  1566. 

Lemnius,  (Levinus,)  Occulta  Naturae  Miracula.  8vo.    Antwerp,  1567. 
Mizaldus,  (Anton.,)  Memorabilium  Utilium  et  Jucundorum  Centuria 

IX.    8vo. 


V     'APPENDIX.  467 

Cellini,  (Benvenuto,)  Del  Arte  del  Gioiellare.    4to.    Fior.  1568. 
Albert!,  (Magni,)  De  Mineralibus  et  rebus  metallicis.     Libri  V.  8vo. 

1541, 1569. 

Mizaldus,  (Anton.,)  Secrets  de  la  Lune.    Svo.    Paris,  1571. 
Athenaeus,  Deiphnosophistae,  (Banquet  des  Pliilosopb.es,)  traduit  par 

Dalecbamp.    Paris,  1573. 
Marbodaaus,  (Gallus,)  De  Gemmarum  Lapiduinque  pretiosorum  for- 

mis  atque  viribus  opusculum.    8vo.     Colon.  1593 ;  12mo.    Ba#. 

1555  ;  12mo.    Lubec,  1575. 
Belleau,  (Rene,)  Les  Amours  et  nouveaux  Changes  des  Pierres  pre 

cieuses.    4to.    Paris,  1576. 
Evax,  (a  King  of  the  Arabs,)  a  MS.  is  attributed  to  him  on  the 

properties  and  effects  of  precious  stones,  published  by  Henry 

Rantzovius,  under  the  title  "  De  Gemmis  scriptum  olim  a  poeta 

quodam  non  infeliciter  carmine  redditum  et  nunc  primum  in  lucem 

editum."    4to.     Leipsic,  1585. 

Bacci,  (Andrea,)  Le  XII.  Pietre  preziose.  '  4to.    Roma,  1587. 
Cnesalpin,  (A.,)  De  re  metallica.    4to.    Romce,  1596. 
Porta,  (Giov.  Baptista,)  A  Method  of  Knowing  the  Inward  Virtues 

of  Kings  by  Inspection.    Fol.    Neapoli,  1601. 
Arnobio,  (Cleandre,)  II  Tesoro  delle  Gioie,  trattato  maraviglioso. 

Venet.  1602.  ^ 

Bacci,  (Andrea,)  De  Gemmis  et  Lapidibus  pretiosis,  tractatus  ex  Ital. 

Lingua  Lat.  red.     8vo.    Franco/,  1605. 
Fernel,  (John  Francis^)  Pharmacia,  cum  Guliel.  Plantii  et  Franc. 

Saguyerii  Scholiis.    12mo.    Hanov.  1605. 
Morales,  (Gasp,  de,)  Libro  de  las  Virtudes  y  Propriedades  maravil- 

losas  de  las  Piedras  preziosas.    8vo.    Madrid,  1605. 
Porta,  (Giov.  Baptista,)  De  DistiUationibus.    4to.    Rome,  1608. 
Avicennaa  Opera.    Roma?,  1593.     Venetiis,  1608. 
Ferrante  Imperator :  De  fossilibus  opusculum.    4to.    Napoli,  1610. 
Portaleone,  (Abraham,)  Shilte  Haggeborim.    (The  Shields  of  the 

Mighty.)    Heb.  Mantua,  (A.  M.  5372,)  1612. 
Clutius,  (Augerius,)  Calsvee,  sive  Dissertatio  Lapidis  Xephrititri,  seu 

Jaspidis  viridis,  naturam,  proprfetates,  et  operationes  exhibens 

Belgice.    8vo.    Amsterdam,  1621,  et  Lat.  per  Gul.  Lauremberg, 

fil.    8vo.    Rostochii,  1627. 
Bacci,  (Andrea,)  De  Gemmis  ac  Lapidibus  pretiosis  in  S.  Scriptura. 

4to.    Rome,  1577 ;  8vo.  Franc.  1628. 
Jonstonus,  (Johannes,)  Thaumatographia  Naturalis.    12mo.    Amst. 

1632, 


468  APPENDIX.*        * 

Clave,  (Estienne,)  Paradoxes,  ou  Traittez  PMlosopliiques  desPierres 

et  Pierreries,  centre  1'opinion  vulgaire.  8vo.  Paris,  1635. 
Csesius,  (Bernardus,)  De  Mineralibus.  Fol.  Lugduni,  1636. 
Toll,  (Adrianus,)  Gemmarum.  et  Lapidum  Historia.  8vo.  Lugduni, 

1636. 
Boot,  (Anselmus  Boetius  de,)  Gemmarum  et  Lapidum  Historia.    4to. 

Hanover,  1690.    Recensuit  et  commentariis  illustravit  Adr.  Toll. 

8vo.    Lugd,  Batav.  1636. 
Boot,  (Ans.  Boe'ce  de,)  Le  Parfaict  Joaillier,  ou  Histoire  des  Pierreries, 

de  nouveau  enriclii  de  belles  Annotations  par  Andre  Toll,  trad,  du 

Lat.  par  J.  Bachou.    8vo.    Lyon,  1644. 
Toll,  (Adr  anus,)  Le  Parfaict  Joiillier,  ou  Histoire  des  Pierreries,  ou 

1 01 1  amplement  descrites  leur  naissance,  juste  prix,  etc.     8vo. 

Lyon,  1644. 
Laet,  (Jo.  de,)  De  Gemmis  et  Lapidibus,  Lib.  II.  Gr.  et  Lat.    Part*, 

1647. 
•Ecchellensis,  (Abraham,)  Versio  Durrhamani  de  Medicis  Virtutibus 

animalium,  plantarum  et  Gemmarum.    8vo.    Pans,  1647. 
Habdarralimanus,  (Asiutensis  ^Bgyptius,)  De  Proprietatibus  ac  Vir- 
tutibus medicis  Animalium,  Plantarum  ac  Gemmarum,  ex  Arab. 

Lat.  redd,  ab  Abrahamo  Ecchellenst    8vo.    Paris,  1647. 
Laet,  (John  de,)  De  Gemmis  et  Lapidibus  Libri  II.,  quibus  prsemit- 

titur  Theophrasti  Liber  ;  de  Lapidibus  Gr.  Lat.,  cum  Annotationi- 
-  bus.    8vo.    Ludg.  Bat.  1647. 
Boetius,  (de  Boot,)  Gemmarum  et  Lapidum  historia,  quam  olim 

edidit  Ans.  B.  de  Boot,  postea  Adrianus  Tollins  recensuit.     Tertia 

Edit,  longe  purgatissima.    Cui  accedunt  Jo.  de  Laet,  de  gemmis 

et  lapidibus  Libri  II.,  et  Theophrasti  liber  de  Lapidibus.    8vo. 

Lugduni  Batawrum,  1647. 
Paracelsus,  (Philippus  Aurelius  Theophrastus,)  Nine  Books  on  the 

Nature  of  Things ;  into  English  by  J.  F.    4to.    London,  1650. 
Nichols,  (Thomas,)  Arcula  Gemmea ;  or,  the  Nature,  Virtue  and 

Valour  of  Precious  Stones,  with  Cautions  for  those  who  deal  in 

them.    4to.    Cambridge,  1652. 
Nichols,  (Thomas,)  A  Lapidary,  Vr  History  of  Pretious  Stones  ;  with 

Cautions  for  the  undeceiving  of  all  those  that  deal  with  Pretious 

Stones.    4to.    Cambridge,  1652. 

Hermes  Trismegistus,  Tabula  Smaragdina  vindicata.    12mo.    1657. 
Nichols,  (Thomas,)  Gemmarius  Fidelis,  or  the  Faithful  Lapidary ; 

experimentally  describing  the  richest  Treasures  of  Nature,  in  an 

Historical  Narrative  of  the  several  Natures,  Virtues  and  Qualities 


APPENDIX.  469 

of  all  Precious  Stones,  "with  a  Discovery  of  all  such  as  are  Adul- 
terate and  Counterfeit.    4to.    London,  1659. 
Lowell,  (Robert,)  Panzoologicomineralogia,  or  a  History  of  Animals 

and  Minerals.    12mo.     Oxford,  1661. 
Johnson,  (J.,)  Notitia  regni  mineralis,  sive  Catalogus  subterraneorum 

cum  prsecipuis  differentiis.     12mo.    Lipsice,  1661. 
Berquen,  (Robert  de,)  Les  Merveilles  des  Indes  Orientales  et  Occi- 

dentales,  ou  nouveau  Traite  des  Pierres  precieuses  et  des  Perles. 

4to.    Pflrw,.1661. 
Jonstonus,  (J.,)  Notitia  Regni  Yegetabilis  et  Mineralifl.    12mo.   Lips. 

1661. 
Boyle,  (Hon.  Robert,)  Experiments  and  Considerations  upon  Colour, 

with  Considerations  on  a  Diamond  that  Shines  in  the  Dark.    8vo. 

London,  1663. 
Kircheri,  (Athanasii,)  Mundus  subterraneus  in  Libros  XII.,  digestus. 

With  plates  and  portraits  of  Kircher  and  Pope  Alexander.    Fol. 
.  Amsterdam,  1665. 
Histoire  des  Joyaux  et  des  principales  Richesses  de  1'Orient  et  de 

1'Occideat.    12mo.    Geneve,  1665. 
M.  L.  M.  D.  S.  D.,  Denombrement,  FacultS  et  Origine  des  Pierres 

precieuses.    Post  8vo.    Paris,  1667. 

Schmid,  (Joachimus,)  De  Margaritis.    4to.     Wtttebergce,  1667. 
Rhosnel,  Le  Mercure  Indien.    Paris,  1668. 
Piererus,  (G.  P.,)  Lazulus,  Dissertatio  chymico-medica.    4to.    Ar- 

gentarati,  1688. 

Aldrovandi,  (Ulyssis,)  Opera  Omnia.    3  vols.  fol.  with  several  thou- 
sand wood  cuts.    B&nonice,  1599-1668. 

Tesoro  deUe  Gioie,  Trattato  Curioso.    12mo.     Venetia,  1670. 
History  of  Jewels.    12mo.    London,  1671. 
Steno,  (Nicolaus,)  Prodromus  to  a  Dissertation  concerning  Solids 

naturally  contained  within  Solids.    London,  1671. 
Boyle,  (Hon.  Robert,)  An  Essay  about  the  Origin  and  Virtues  of 

Gems,  with  some  Conjectures  about  the  Consistence  of  the  Matter 

of  Precious  Stones,  etc.    London,  8vo.    1672,  and  12mo.  1673. 
Sandius,  (Christopher,)*  On  the  Origin  of  Pearls.     Phil.   Trans. 

1674. 
Tavernier,  Voyages  en  Turquie,  enj'erse  et  aux  Indes.   4to.   Paris, 

1676. 
Kircher,  (Athanasius,)  Mundus  Subterraneus  in  XII.  Libros  digestus.  0 

Fol.    Ainstellodami,  1678. 
Blumenberg,  Dissertatio  Medica  de  Succino.    4to.    Jena,  1682. 


470  APPENDIX. 

Kirani,  Kiranedes,  et  ad  eas  Rhyakini  Koronides,  sive  Hysteria 

Physico-Medica.     12mo..  London,  1685. 
Konig,  (Emanuel,)  Regnum  Minerale,  physice,  inedice,  anatomice, 

alcliymice,  analogice,  tlieoretice  et  practice  investigatum.    4to. 

Basil,  1687. 
Orpheus,  (1260  B.  C.,)  Hymni  et  de  Lapidibus,  Gr.  Lat.,  curante  A. 

C.  Eschenbachio ;  accedunt  H.  Stepliani  notae.    8vo.    Traj.  ad  Rh. 

1689. 
Panthot,  (Jean  B.,)  Trait  e  des  Dragons  et  des  Escarbqucles.    Small 

12mo:    Lyon,  1691. 
•Hiaerne,  (Urban,)  Kort  Anledning  til  askillige  Malm  och  Bergarters, 

Mineraliers,  etc. ;  eftersporjande  och  angifvande.    Stockholm,  1694. 
Hiller,  (Matth.,)  Tractatus  de  Gemmis  XII.  in  Pectorali  Pontificis 

Hebraeorum.     4to.     Tubingen,  1698. 
Slevogtii,  (J.  H.,)  De  Lapide  Bezoar.    4to.    Jena,  1698. 
Venette,  (Nicolas,)  Trait6  des  Pierres.     12mo.    Amst.  1701. 
Strachan,  Observations  on  Coral,  large  Oysters,  Rubies,  etc.    Abr^ 

ii.  711.    Phil.  Trans.  1701. 
Gulielmini,  De  Salibus  dissertatio  physica,  medico-mechanica.     Ve- 

netiis,  1705. 

Curiose  Speculationen.    Leipzig,  1707. 

Description  of  the  Diamond.    Phil.  Trans.  Abr.  ii.  405.    1708. 
Chambon,   Traite   des  Metaux  et   des  Mineraux.    12mo.    Paris, 

1714. 
Leisnerus,  (Gott.   Christ.,)  De  Coralliorum  Natura,  Proeparatis  et 

Usibus.     Wittembergw,  1720. 
Cappeller,  (Maur.  Ant.,)  Prodomus  Crystallographise,  de  Crystallis 

iinproprie  sic  dictis  Commentarium.    4to.    Lucernce,  1723. 
Henckel,  (J.  Fr.,)  Pyritologia.    8vo.    Lip&im,  1725. 
Woodward,  (Dr.  J.,)  Fossils  of  all  kinds  digested  into  a  method  suit- 
able to  their  mutual  relation  and  affinity.    With  plates.    London, 

1728. 
Woodward,  (Dr.  J.,)  An  attempt  towards  the  Natural  History  of  the 

Fossils  of  England,  in  the  collection  of  J.  Woodward.    8vo.    Lon- 
don, 1729. 

Memoires  de  Regne  de  Catherine,  Imperatrice  de  Russie.    Amster- 
dam, 1729. 

Bourget,  Lettres  sur  la  Formation  des  Sels  et  Cristaux.     12mo. 
%  Amst.  1729. 
Bromel,  (Magn.  von,)  Inledning  til  nodig  Kundskap  om  Bergarter, 

Mineralier,  Metaller,  samt  Fossil ier.    8vo.    Stockholm,  1730. 


APPENDIX.  471 

Gimma,"  (D.  Giacinto,)  Delia  Storia  naturale  dell^  Gemme,  delle 

Pietre  e  di  tutti  Mineral!,  owero  della  Fisica  sotteranea.    4to. 

Napoli,  1730. 
Sarmento,  (James  Castro  de,  M.  D.,)  An  Account  of  Diamonds  found 

in  Brazil.    Phil.  Trans.  Abr.  vii.  503.    1731. 
Henckel,  (J.  Fr.,)  Idea  generalis  de  Lapidum  origine.    8vo.    Dresd. 

et  Lips.  1734. 
Colonne,  (Francois  Marie  Pompee,)  Histoire  Naturelle  de  TUnivers. 

4  vols.  8vo.    Paris,  1734. 
Pluche,  (1'Abbe  Antoine  Noel  de,)  Spectacle  de  la  Nature.    4to. 

Paris,  1732-39. 

Becher,  (John  Joachim,)  Physica  Subterranea.    4to.    Lipsice,  1739. 
Argenville,  Traite  de  1'Oryctologie.    Paris,  1740. 
Marbodaeus,  De  Lapidibus  pretiosis  Enchiridion,  cum  Scholiis  Pic- 

torii.    4to.     Wolfenbuttelce,  1740. 
Swedenborgii,  (Emanuelis,)  Opera  Philosophica  et  Mineralia.    3 

vols.  fol.,  with  numerous  plates.    Paris,  1743. 
Argenville,  (A.  J.  D.  d',)  De  1'Histoire  Naturelle  eclaircie  dans  deux 

de  ses  parties  principales  :  la  Lithologie  et  la  Conchologie.    4to. 

Paris,  1743. 
Elliott,  (John,  F.  R.  S.,)  on  the  Specific  Gravity  of  Diamonds.'  Phtt. 

Trans.  Abr.  ix.  147.    1745. 
St.  Laurent,  (Joanon  de,)  Description  abregee  du  fameux  Cabinet  de 

M.  le  Chevalier  de  Baillon,  pour  servir  a  1'histoire  naturelle  des 

Pierres  precieuses,  etc.    Luques,  1746. 

Theophrastus,  History  of  Stones,  with  the  Greek  Text  and  an  Eng- 
lish Version,  and  Notes  Critical  and  Philosophical,  including  the 

Modern  History  of  Gems  described  by  that  Author,  by  Sir  John 

Hill.    8vo.    London,  m$. 

Kahler,  (Mart.,)  De  Crystallorum  Generatione.    4to.     Upsal,174X. 
Henckel,  (J.  Fr.,)  In  Mineralogia  redivivus.    8vo.    Dresdw,  1747. 
Wallerius,  (J.  G.,)  Mineralogia  eller  Mineral  Ricket  indelt  och  besk- 

rifvet.   8vo.    Stockholm,  1747. 
Dingley,  (Robert,  Esq.,)  On  Gems  and  Precious  Stones,  particularly 

such  as  the  Ancients  used  to  engrave  on.    Phil.  Trans.  Abr.  ix. 

345.    1747. 

Hill,  (Sir 'John,)  The  History  of  Fossils.    London,  1748. 
Leonardus,  (Camillus,)  The  Mirror  of  Stones,  in  which  the  Nature, 

Generative  Properties,  Virtues  and  Various  Species  of  more  than 

200  different  Jewels,  Precious  and  Rare   Stones  are  distinctly 

described.    8vo.    London,  1750. 


472  APPENDIX. 

Mariette,  (P.  J.^  Trait6  des  Pierres  gravies.    Fol.    Paris,  1750. 

Jeffries,  (David,  Jeweller,)  Treatise  on  Diamonds  and  Pearls,  in  which 
their  importance  is  considered,  plain  rules  are  exhibited  for  ascer- 
taining the  value  of  both,  and  the  true  method  of  manufacturing 
Diamonds  is  laid  down.  8vo.  30  copper  plates.  Published  by 
subscription.  London,  1750-51  and  1753. 

Jeffries,  (D.,)  Trait6  des  Diamants  et  des  Perles.    8vo.  .  Paris,  1753. 

Pott,  (M.  J.,)  Lithogeognosie,  ou  Examen  chymique  des  Pierres  et 
des  Terres  en  general  et  de  la  Topaze  et  de  la  Steatite  en  particu- 
lier.  8vo.  Paris,  1753. 

Jeffries,  (David,)  An  Abstract  of  the  Treatise  on  Diamonds  and 
Pearls,  by  which  the  usefulness  to  all  who  are  any  way  interested 
in  these  jewels  will  sufficiently  appear,  and  therefore  addressed  to 
the  nobility  and  gentry  of  this  kingdom,  and  to  the  traders  in 
jewels.  8vo.  Baldwn,  London,  1754. 

Natter,  (Laurentius,)  A  Treatise  on  the  Ancient  Method  of  Engrav- 
ing Precious  Stones  compared  with  the  Modern.  Fol.  London, 
1754. 

Traite  des  Pierres  _de  Theophraste,  trad,  du  Grec.  12mo.  Paris, 
1754. 

Salerne,  L'Oryctologie.    4to.    Paris,  1755. 

Cartheuser,  Elementa  Mineralogise  systematice  disposita.  8vo.  Fran- 
co/. 1755. 

Kalm,  (P.,)  Nagra  Kannemarken  til  nyttiga  Mineraliens  eller  ford 
och  Baigarters  upfinnande.  4to.  Aboce,  1756. 

Da  Costa,  (E.  Mendes,)  Natural  History  of  Fossils.  4to.  London, 
1757. 

Pott,  (J.  H.,)  Chemische  tlntersuchungen,  welche  vornehmlich  von 
der  Litheognosie  handeln.  4to.  Potsdam,  1746  ;  also  1751-54 
and  1757. 

Woltersdorf,  (J.  L.,)  Systema  minerale  in  quo  regni  mineralis  pro- 
ducta  omnia  systematica  per  classes,  ordines,  genera,  et  species 
proponuntur.  4to.  Berlin,  1738 ;  also  1753-4,  and  1755-8. 

Cronstedt,  (Axel  von,)  Forsok  til  Mineralogia  eller  Mineral-rikets  Up- 
stallning.  8vo.  Stockholm,  1758. 

Bomare,  (Valmont  de,)  Prospectus  d'un  cours  surl'histoire.Naturelle 
des  Mineraux.  12mo.  Paris,  1759. 

Gerhard,  (C.  A.,)  Disquisitio  physico-chemica  Granatorum  Silesiae 
atque  Bohemise.  Inaug.  Diss.  4to.  Frankfurt  a.  d.  Oder,  1760. 

Gronovii,  (L.  T.,}  Bibliotheca  Regni  Animalis  et  Lapidei.  4to.  Luyd. 
Bat.  1760. 


APPENDIX.  473 

Natter,  (Lgurentius,)  Catalogue  des  Pierres  gravies  de  My  lord  Comte 

de  Besborougli.     4to.     London,  1761. 
Pouget,  (N.,)  Traite  des  Pierres  precieuses,  et  de  la  maniere  de  les 

employer  en  parure.    4to.    Paris,  1762. 
Vogel,  (R.  A.  Praes.,)  Terrarum  atque  lapidum  partitio,  resp.  A.  Fr. 

Hempel.    4to.     Gdttingen,  1762. 
Walch,  (J.  E.  J.,)  Das  Steinreich  systematischentworfen.     2  vols. 

8vo.    24  plates.    Halle,  1762. 
Bertrand,  (E.,)   Dictionnaire  universel  des  fossiles  propres  et  des 

fossiles  accidentels,  contenant  une  description  des  Terres  Sables, 

&c.    8vo.    2  vols.  in  1.    La  Haye,  1763. 
'Pheopliylacti  Opera,  a  J.  F.  Bern,  de  Rubeis  et  Borif.  Finettio, 

Greec.  et  Lat.    4  vols.    Fol.     Venet.  1754  and  1763. 
Justi,  (J.  H.   G.,)  Grundriss  des  gesammten  Mineralreiclis.    8vb. 

Gdttingen,  1757 ;  also  in  1765. 
Linnaeus,  (C.,)  Systema  Naturae  sive  tria  regna.     Ed.  I.     Fol.  Lugd.. 

Bat.  1735.    Ed.  XII.,  Holmice,  1766. 
Bertrand,  (E.,)  Recueil  de  divers  TraiteV  sur  1'Histoire  Naturelle  de 

la  Terre  et  des  Fossiles.    4to.    Avignon,  1766. 
Bock,  (Fr.  S.,)  Vesucb  einer  kurzen  Naturgeschicbte  des  Preussischen 

Bernsteins,  und  einer  neuen  warscbeinlichen  Erklarung  seines 

Ursprunges.    8vo.    Kdnigsberg,  1767.    ' 
Wallerius,  (J.  G.,)  Lucrubrationum  arademicarum  specimen  primum 

de  systematibus  mineralogicis  et  systemate    mineralogico  rite 

condendo.    8vo.    Holmice,  1768.  * 

Scopoli,  (J.  -A.,)  Einleitung  zur  Kenntniss  und  Gebrauch  der  Fos- 

silien.    8vo.    Riga  und  Milan,  1769. 
Baumer,  (John  Willi^  Historia  Naturalis  Lapidum  preciosorum 

omnium,  etc.    8vo.    Franc.  1771. 

Bourguet,  Du  Regne  Minerale.    4  vols.  12mo.    Paris,  1771. 
Forster,  (J.  R.,)  ClassiJBcation  of  Fossils  and  Minerals.    London, 

1768 ;  also  in  1772. 
Scopoli,  (J.  A.,)  Principia  Mineralogiaa  systematic^  et  practical. 

Pragcs,  1772. 
Juwelier,  Der  Aufrichtige,  oder  Anweisung  aller  Arten  Edelsteine, 

•Diamanten,    und    Perlen    zu  erkennen,    nebst    einer  aus   dem 

Engliscben  iibersetzten  AbbandJung  von  den  Diamenten  und 

Perlen.    8vo.    Frankfurt,  1772. 
Hodgson,  (Rev.  Jobn,)  Dissertation  on  an  Ancient  Cornelian.  ArcJwol. 

ii.  42.     1773. 


474  APPENDIX. 

Bruckmann,  (U.  F.  B.,)  Abhandlung  von  Edelsteinen.   Braunschweig, 

1757-73. 
Baiimer,  (J.  W.,)  Naturgeschichte  aller  Edelsteine,  wie  auch  der 

Erde  und  Steine,  so  bisher  z'ur  Artznei  sind  gebraucht  worden. 

Aus  dem  Latein.  von  Karl,  Freih.  von  Meidinger.    8vo.     Wien, 

1774. 
Schroter,  (J.  S.,)  Journal  fiir  die  Liebhaber  des  Steinreichs.   Weimar, 

1774. 
Werner,  (Abr.  G.,)  Vender  ausserlichen  Kennzeichen  der  Fossilien. 

8vo.    Leip.  1774. 

Bruckmann,  (Fr.  Hier.,)  A  Treatise  on  Precious  Stones.     8vo.    1775. 
Born,  (Baron  Inigo,)  Schneckensteine,  oder  die  Sachsischen  Topas- 

felsen.    4to.    Prag.  1776. 
Collini,  (Cosmus,)  Journal  d'un  Voyage,  qui  contient  differentes 

observations  rnineralogiques,  particulierement  sur  les  agates,  avec 
.    un  detail  sur  la  maniere  de  travailler  les  agates.  8vo.  Manrilieim, 

1776. 
Dutens,  (Lewis,)  Des  Pierres  precieuses  et  des  Pierres  fines,  avec  les 

moyens  de  les  connoitre  et  de  les  valuer.    Londres,  1776. 
Scopoli,  (Jo.,)  Ant.  Crystallographia  Hungarica.  4to.  Prague,  1776. 
Vogel,  (R.  A.,)  Practisches  Mineralsystem.    2d  ed.    8vo.  Leip.  1776. 
Sage,  Mineralogie  docim'astique,  with  plates.    8vo.    Paris,  1772 ; 

also  in  2  vols.  in  1777. 
Wallerius,  (J.  G.,)  Systema  Mineralogicum,  quo  Corpora  Mineralia 

in  classes,  ordines,  genera  et  species,  suis  cum  va'r.  divisa  descri- 

buntur  atque  observationibus,  experimentis  et  figuris  illustrantur. 

2  vols.    8vo.     Vindob.l™. 
Bruckmann,  (U.  F.  B.,)  Gesammelte  und  eigane  Beitrage  zu  seiner 

Abhandlung  von  Edelsteinen.    Braunschweig,  1778. 
Bomare,  (Valmont  de,)  Mineralogie,  ou  nouvelle  exposition  de  Regne 

Minerale.    8vo.    Pa/ris,  1769  ;  also  in  1774,  1780. 
Fichtel,  (J.  C.  Von,)  Mineralgeschichte.    4to.,  with  plates.    Ham- 
burgh, 1780. 

Haiiy,  (Abbe  de,)  Traite  de  la  Mineralogie.    Paris,  1780. 
Regenbogen-Achat,  Vom.    4to.    Hamburgh,  1780. 
Gerhard,  (C.  A.,)  Beitrage  zur  Chemie  und  Geschichte  des  Mmeral- 

reichs.    2  vols.  8vo.    Berlin,  1773-1776 ',  also  in  1781. 
Lenz,  (J.  G.,)  Tabellen  iiber  das  gesammte  Steinreich.   4to.    Jena, 

1781. 
Bergmann,  (T.,)  Sciagraphia  regni  mineralis  secundum  principia 

proxuna  digesti.    8vo.    Lipsice,  1782. 


APPENDIX.  475 

jjj    • 
Buchoz,  Lee  Dons  merveilleux  et  diversement  colories  de  la  Nature 

dans  le  Regne  Mineral.    Fol.    Para,.  1783. 
(^.rosi,  (Johann,)  Sur  la  Generation    du  Silex  du  Quarz.     8vo. 

Oracm.  1783. 
Rome  de  L'Isle,  Essai  de  Cristallographie.    8vo.    Paris,  1772.    2d 

ed.  in  4  vols.    8vo.    1783. 
M.  Buffon,  (Le  Comte  de,)  Histoire  Naturelle  des  Mineraux.    4to. 

Paris,  1783. 
Faujas  de  Saint  Fond,  (B.,)  Mineralogie  des  Volcans  ou  Description 

de  toutes  les  substances  produits  ou  rejetees  par  les  feux  souter- 

rains.    Royal  8vo.    Paris,  1784. 
Daubenton,  Tableaux  methodiqtie  des  Mine'raux  suivant  leurs  dif- 

ferentes  natures.    4to.    Paris,  1784. 
Ravius,  (S.  F.,)  Specimen  Arabicum,  continens  descriptionem  et  ex- 

cerpta  libri  Achmedis  Teifascbii  '  De  Gemmis  et  Lapidibus  Pre- 

tiosis/  Arabic.    Trapetum  ad  Rhenum,  1784. 
Haiiy,  (Rene  Just.,)  Essay  d'une  Theorie  BUT  la  structure  des  Cris- 

taux.    8vo.    Paris,  1784.  •  :- 

Cadet,  (Le  Jeune,)  Memoire  sur  les  Jaspes  et  autres  Pierres  pre- 

cieuses  de  1'ile  de  Corse,  etc.    8vo.    Bastia,  1785. 
Genuine  Account  of  the  present  state  of  the  Diamond  Trade  in  the 

Dominions  of  Portugal,  with  some  authentic  pieces,  in  a  letter 

from  a  merchant  in  Lisbon  to  his  Correspondent  in  London.    4to. 

L<md<m,  1785.! 
Well,  (J.  J.  von,)  Methodische  Einleitung  der  mineralogischen  Kor- 

per.    8vo.     Wien,  1786. 

CavaUo,  (Tib.,)  Mineralogical  Tables.    Fol.    Lvndm,  1786. 
Schopf,  (J.  D.,)  Beytrage  zur  Mineralogischen  Kenntniss  des  ostlichen 

Theils  von  Nordamerika,  und  seiner  Gebirge.    8vo.    1787. 
Walker,  Classis  Fossilum,  sive  characteres  Naturales  chymici  clas- 

sium  et  ordinum  hi  Systemate  Minerali.    8vo.    Edwburg,  1787. 
Fibig,    Handbuch   der   Mineralogie.    8vo.     Mainz   und   Frankf. 

1787. 
Volta,  (Ab.,)  Element!  di  Mineralogia  anahtica  e  sistematica.    8vo. 

Pama,  1787. 
Miiller,  (J.,)  Nachricht  von  den  in  Tyrol  entdeckten  Tunualinen,  oder 

Aschenziehern,  von  Ignaz  EdeLa  von  Born.    4to.     Wien,  1787.     ^ 
Williams,  (John,)  Natural  History  of  the  Mineral  Kingdom.    2  vols. 

8vo.    Edinb.  1789. 
Schall,  (C.  F.  W.,)  Anleitung  zur  Kenntniss  der  besten  Biicher  in  der 

Mineralogie.    2d  edit.    8vo.     Weimar,  1789. 


476  APPENDIX. 

De  Born,  Catalogue  de  la  collection  des  Fossiles  de  Eleonore  de 

Raab.    2  vols.    8vo.     Vienna,  1790. 
Lenz,  (J.  G.,)  Mineralogisclies  Handbucli  durch  weitere  Ausfuhrui% 

des  Wernerschen  Systems.    8vo.    Hildburghausen,  1791. 
Catalogue  des  Bijoux  nationaux.    Paris,  1791. 
Lehman,  (J.  A.,)  Entwurf,  einer  Mineralogie.    8vo.    Frank/,  et  Leip. 

1857  ;  also  in  1769  and  1791. 
Gallitzin,  (Le  Prince  Dimitri  de,)  Traite  ou  Description  abregee 

methodiques' des  Mineraux.    4to.     Maastricht,  1792. 
Emmerling,  (L.  A.,)  Lehrbuch  der  Mineralogie.    8vo.    Giezen,  1793. 
Veltheim,  (A.  V.  von,)  Reformen  in  der  Mineralogie.     8vo.     Helm. 

1793. 
Bekkerheim,  (Karl,)  Krystallographie  des  Mineralreichs.  8vo.  Wien, 

1793. 
Veltheim,  (A.  F.  von,)  Etwas  iiber   Memnons  Bildsaule,  Nero's 

Smaragd,  Toreutik,  und  die  Kunst  der  Alten  in  Stein  und  Glas 

zu  sclmeiden.     8vo.    Helmstadt,  1793. 

Wulfinii  Descriptlo  Helmintholiti  pulcherrimi  versicoloris  in  mar- 
more  Corinthiaco.    4to.    Erlangce,  1794. 
Lenz,  (J.  G.,)  Vollstandig  Einleitung  zur  Kenntniss  der  Mineralien. 

2  vols.    8vo.    Leipz.  1794. 
Kirwan,  (R.,)  Elements  of  Mineralogy.    8vo.    London,  -1784 ;  2d 

ed.  1794. 
Schmeisser,  (J.  G.,)  System  of  Mineralogy.    Vol.  1.    8vo.    London, 

1794. 

Wiedenmann,  Handbuch  der  Oryktognostichen  Theils  der  Mineralo- 
gie.   2  vols.    8vo.    Leipzig,  1794.  . 
Del  Rio,  (Don  Andres  Manuel,)  Elementos  de  Oryktognosia  6  del 

conocimiento  de  los  fossiles,  dispuestos  segun  los  principios  de  A. 

G.  Werner.    .4to.    Mexico,  1795. 
Retzius,  (A.  J.,)  Forsok  til  Mineral-Rikets  Upstallning.    8vo.  Lund. 

1795. 
Forster,  (J.  R.,)  Onomatologia  nova  systematis  oryktognosise,  voca- 

bulis  latinis  expressa.    Fol.    Halce,  1795. 
Psellus,  )Michael  Cohstantinus,)  De  Lapidum  Virtutibus,  Gra3ce  ac 

Latine.    8vo.    Lugduni  Batavorum,  1795. 
^abington,  (Charles,)  A  Systematic  Arrangement  of  Minerals,  their 

Chemical,  Physical,  and  External  Characters.  4to.  London,  1795. 
Ekeberg,  (Andrew  Gustavus,)  Dissertatio  de  Topazio.  Ifpsal,  1796, 
Hasse,  (J.  H,  F..)  Der  Aufgefundene  Eridanus,  oder  neue  Aufsch- 

lus,se  iiber  den  Ursprung  des  Bernsteins.    8vo.     Riga,  1796. 


APPENDIX.  477 

Napione,  Element!  di  Mineralogia.    8vo.     Turin,  1796. 

Gerhard,  (G.   A.,)  Grundriss  des  Mineralsystems.      8vo.    Berlin, 

1786  and  1797. 
Andrada,  (M.  d',)  An  Account  of  the  Diamonds  of  Brazil.     Nich. 

Journ  i.  24     1797. 

* 

Diamond,  The,  or  the  Pest  of  a  Day.     Fores.     4to.     London,  1797. 
Tennant,  (Smithson,  Esq.,  F.  R.  S.,)  On  the  Nature  of  the  Diamond. 

Phil.Trans  1797,  xviii  97,  and  Nich.  Journ.  i.  177.    1797. 
Veltheim,  (A.  F.  von,)  Etwas  iiber  das  Onyx-Gebirge  des  Clesias 

und  den  Handel  der  Alten  nach  Ost-Indien.    8vo.    Helrwtadt,  1 797. 

Bouruon,  (Count  de,)  An  Analytical  Description  of  the  "Crystalline 

.Forms  of  Corundum  from  the  East  Indies  and  China.     Phil. 

Trans.  At>r.  xviii  368.    1798. 
Struve,  (H.,)  Methode  Analytique  desFossiles,  fondee  surleurs  Carac- 

teres  Exterieurs.    8vo.    Lausanne,  1797  ;  8vo.    Paris,  1798. 
Townson,  (R.,)  Philosophy  of  Mineralogy.    8vo,    Plates.    London, 

1798. 
Reuss,  (F.  A.,)  Lexicon  Mineralogicum,  sive  Index  Latino-Gallico- 

Suecico-Danico-Angnco-Russico-Hungarico-Germanicus    Minerali- 
*mn.    8vo.    Cura  Regis.    Leip.  1798. 
GreviUe,  (Rt.  Hon.  Charles,  F.  R.  S.,)  On  the  Corundum  Stone  from 

Asia.    Phil.-  Tram.  Abr.  xviii.  356, 1798,  and  NicJi.  Journ, ii,  477. 

1799. 
Guyton-Morveau,  (B.  L.,)  Verbal  Process  of  the  conversion  of  Soft 

Iron  into  Cast  Steel  by  means  of  the  Diamond.    Nich.  Journ.  iii. 

353.    1799. 
Klaproth,  (Martin  Henry,)  Analysis  of  the  Spinel.    Nich.  Journ,  iii. 

549.    1799. 
Palm,  (J.  J.,)  Dissertatio  gradualis  sistens  observationes  nonnullas 

de  Lapide  Obsidiano.    4to.    Londoni  Gothorum,  1799. 
Babington,  A  Systematic  Arrangement  of  Minerals.    4to.    London, 

1795 ;  1799. 
Batsch,  (A.  J.  G.  K.,)  Versuch  einer  Anleitung  zur  Kenntniss  und 

Geschiehte  der  Thiere  und  Mineralien.    2  Bde.    8vo.    Jena,  1788, 

1789  ;  also  1796-1800. 
Jameson,  (Robert,)  Mineralogy  of  the  Scottish  Isles.    Maps  and 

Plates.    2  vols.  4to.    Edinburgh,  1800. 
Brunner,  (J.,)  Versuch  einer  neuen  Systems  der  Mineralogie.    8vro. 

Leipzig,  1800. 
Blindheim,  (J.  J.,)  Ueber  den  Sibirischen  und  Taurischen  Kalzedon. 

Neue  Schrift.  der  GeseUsch.  naturf.  Freunde.    4to.    Berlin,  18CO. 


478  APPENDIX. 

Mackenzie,  (Sir  Geo.  Stewart,  Bart.,  F.  R.  S.  L.  &  E.,)  Experiments 

on  the  Combustion  of  the  Diamond,  the  Formation  of  Steel  by  its 

Combination  with  Iron,  etc.    Nich.  Journ.  iv.  103.    1800. 
BournoH,  (Count  de,)  Description  of  the  Corundum  Stone,  and  its 

Varieties  commonly  known  as  Oriental  Ruby,  Sapphire/  e.tc.    Phil. 

Trans,  p.  223.    1801. 
Kohler,  (H.  K.  A.  von,)  Untersuchung  iiber  den  Sard,  Onyx,  und 

Sardonix.    8vo.    Braunschweig,  1801.  '  «,-V 

Ur,  (Fr.  Ben.,)  Ueber  den  Sarder  Onyx  und  Sardonyx  ;  also,  Nach- 

trag  iiber,  etc.,  1804.    Braunschiceig,  1801. 
Hoff,  (A.  von,)  Magazin  fur  die  gesammte  Mineralogie,  &c.,  pi.    8vo. 

Leipz.  1801. 

Haiiy,  (L'Abbe,)  Traite  de  Mineralogie.    8  vols.    8vo.    Paris,  1801-2. 
Ma  we,  Mineralogy  of  Derbyshire.    8vo.    Plates.    London,.  1802. 
Dolomieu,  (D.  de,)  Sur  la  Philosophic  Mineralogique  et  sur  Fespece 

Mineralogique.    8vo.    Paris,  1802. 
Klaproth,  (Martin  Heinrich,)  Beytrage  zur  Chemischen  Kenntniss 

der  Mineralkorper.    3  B.    8vo.    Berlin,  1795-1802. 
Biehle,  (Von,)  Ueber  die  Bernstein-Grabereien  in  Hinter-Pommeru. 

8vo.    Berlin,  1802. 
Chenevix,  (Richard,  Esq.,  F.  R.  S.,)  Analysis  of  Corundum  and  some 

Substances  that  accompany  it.    Phil.  Trans,  p.  327.     1802. 
Haiiy,  Memoire  sur  les  Topazes  du  Bresil.    Ann.  du  Mus.    Paris, 

1802. 

Schwarze,  (Christ.  Aug.,)  De  Smaragdo  Veterum.  4to.    Gorlicii,  1802. 
Lenk,  (J.,)  Neue  Entdeckung  eines  Steines  Serpentin-Agat.     Wie?i, 

1802. 

Gregor,  (Rev.  William,  M.  A.,)  An  Analysis  of  a  variety  of  the  Co- 
rundum.   Nich.  Journ.  iv.  209.    1803. 
Schwarze,  (Christ.  Aug.,)  De  quodam  Pseudo-Smaragdorum  apud 

veteres  genere.    4to.     Gorlicii,  1803. 

Hausmann,  (J.  F.  L.,)  Krystallogische  Beitrage.    4to.    PL    1803. 
Ludwig,  (C.  F.,)  Handbuch  der  Mineralogie  nach  A.  G.  Werner.- 

8vo.    Leipzig,  1803. 
Lucas,  (J.  A.  H.,)  Tableau  Methodique  des  especes  minerales.    8vo. 

Paris  and  Strasb.  1803. 

Schwarz,  (G.  M.,)  Handbok  i  Oryktognosien.    8vo.    1803. 
Launnas,  (L.  de,)  Mineralogie  des  Anciens.    2  vols.    8vo.    Bruxelles 

and  Paris,  1803. 
Rozin,  Essai  sur  Fetude  de  la  Mineralogie.    8vo.  368  pp.   Bruxelles, 

1803. 


APPENDIX.  479 

Mohs,  (Priederich,)  Handbuch  der  Oryktognosie.   3  vols.  8vo.   Wien, 

1804 
Accmn,  (F.,)  Elements  of  Crystallography,  after  the  manner  of  Haiiy. 

8vo.  plates.    London,  1804. 

Accum,  (F.,)  Analysis  of  Minerals.    12mo.    London,  1804. 
Suckow,  Anfangsgriinde  der  Mineralogie.    8vo.    Leipzig,  1790  ;  2d 

ed.    2  vols.    8vo.     1803-4. 
Haberle,  (C.  C.,)  B^eobachtungen  iiber  die  Gestalt  der  Grand  und 

Keimkrystalle    des    schorlartigen    Berylls,  nnd    dessen  iibrige. 

oryctognostiche  und  geognostische  Verhaltnisse.     Erfurt,  1804. 
Meineke,  (J.  L.  G.,)  Ueber  den  Chrysopras  und  die  denselben  beg- 

leitenden  Fossilien  in  Schlesien.    4to.    Erlangen,  1805. 
Jameson,  (Robert,)  A  Treatise  on  the  External  Characters  of  Minerals. 

8vo.    Edinburgh  and  London,  1804-1805. 
Haberle,  (C.  C.,)  Beitrage  zu  einer  allgemeinen  Einleitung  in  das 

Studium  der  Mineralogie.    8vo.     Weimar,  1805. 
Haberle,  (C.  C.,)  Characterisirende  Darstellung  der  Mineralien  mit 

Hinsicht  auf  Werner  et  Hauy's  beobachtungen.    8vo.     Weimar, 

1806. 
Reuss,  (F.  A.,)  Lehrbuch  der  Mineralogie  nach  Karsten's  Tabellen. 

8vo.    Leipzig,  1801-1806. 
Flade,  (C.  G.,)  De  Re  Metallica  Midianitarum  et  Phoenicorum.    4to. 

Leipzig,  1806. 
Berzelius,  (J.  Jacob,  M.  D.,  F.  S.  A.,)  On  the  Composition  of  the 

Topaz,  etc,    Nich.  Journ.  ix.  105.    1807. 
Brongniart,  Traite  de  Mineralogie,  avec  application  aux  Arts.    Paris, 

1807. 
Eckennan,  (N.,)  Electra,  oder  die  Entstehung  des  Bernsteins.    4to. 

Halle,  1807. 
Pepys,  (William  Hasledine,  Treasurer  of  the  Geol.   Soc.,)  On  the 

Quantity  of  Carbon  in  Carbonic  Acid,  and  on  the  Nature  of  the 

Diamond.    Phil.  Trans,  p.  267,  and  Nich.  Journ.  xix.  267.    1807. 
Brochant  de  Villiers,  (A.  J.  M.,)  Traite  Elementaire  de  Mineraux 

suivant  les  principes  de  Werner.    2  vols.  8vo.  Paris;  also  1807. 
Leonhard,  (C.  C.,)  Taschenbuch  fur  die  gesammte  Mineralogie  mit 

Hinsicht  auf  die  neueste  Entdeckungen.     8vo.     1807. 
Accum,  (F.,)  Manual  of  Analytical  Mineralogy.    2  vols.  PI.  London, 

1808.-  ^ 
Karsten,  (D.  L.  G.,)  Tabellarische  Uebersicht  der  mineralogischen 

einfach.en  Fossilien.    8vo.    2te.  Aufg.    Berlin,  1792 ;  also  1800, 

1808.      ' 


480  APPENDIX. 

Bournon,  (Le  Comte  de,)  Trait  e  de  la   Chaux  Carbonate  et  do 

1'Arragonite,  auquel  on  a  joint  une  introduction  a  la  Mineralogie 

en  general,  une  Theorie  de  la  Crystallisation  et  son  Application. 

4to.    Londres,  1808. 

Brard,  (C.  P.,)  Traite  des  Pierres  precieuses.    Paris,  1808. 
Haiiy,  Sur  la  Reunion  de  la  Pycnite  avec  le  Topaze.    4to.    Pans, 

1808. 
Gautier,  (J.,)  Untersuchung  fiber  die  Entstehung^,  Bildung  und  den 

Bau  des  Cbalcedons,  etc.    Jena,  1809. 
Hausmann,  (J.  F.  L.,)  Entwurf  eines  Systems  der  unorganisirten 

Naturkorper.    8vo.     Cassel,  1809. . 
Weiss,  De  indagando  formarum  crystallinarum  cliaractere  geometri- 

co  principal!.    Lipsice,  1809. 
Lenz,  (J.  G.,)  System  der  Mineralkorper.    8vo.    Bamberg  und  Wurzb. 

1800  ;  also  in  1809. 
Petzl,  (J.,)  Ueber  den  glatten'Beryll  von  Rabenstein  im  Bayrischeri 

Walde.    Abb.  der  Kon.  Akad.    4to.    Munchen,  1809-1810. 
Guyton-Morveau,  (B.  L.,)  On  the  singular  Crystallization  of  the 

Diamond.    Nich.  Journ.  xxv.  67.     1810. 
G  lithe,  (J.  M.,)  Ueber  den  Asterios-Edelstein  des  Cajus  Pliniiis 

Secundus ;    eine  antiquarisch-lithognostische  Abhandlung.     4to. 

Munchen,  1810. 
Fischer,  (G.,)  Essai  sur  la  Turquoise  et  sur  la  Calaite.    Moscou, 

1810. 
Accum,  (F.,)  System  of  Mineralogy  and  Mineralogical  Chemistry. 

4  vols.    8vo.    London,  1810. 
Dree,  (Marquis  de,)  Catalogue  de  Musee  Mineralogique.  4to.   Paris, 

1811. 
Maculloch,  (John,  M.  D.,  F.  'L.  S.,)  Remarks  on.  Several  Parts  of 

Scotland  which  exhibit  Quartz  Rocks,  and  on  the  Nature  and 

Connection  of  this  Rock  in  general.     Geol.  Trans,  i.  450.     1811. 
Chenevix,  (R.,)  On  Mineralogical  Systems.    8vo.    London,  1811. 
Silliman,  (B.,)  Mineralogy  and  Geology  of  New-Haven,  in  a  statistical 

account  of  the  City  of  New-Haven,  by  Pres.  Timothy  Dwight, 

published  by  the  Connecticut  Academy  of  Arts  and  Sciences.  8vo. 

New-Haven,  1811. 
Niizlein,  (F.  A.,  Versuch  eine  neuen  Systems  der  mineralogisch- 

einfachen  Fossilien.    Bamberg  and  Wurzburg,  1810,  1812. 
Lenz,  (J.  G.,)  Erkenntnisslehre  der  Anorganischer  Naturkorper. 

Giesen,  1813. 


APPENDIX.  481 

Lucas,  (J.  A.  H.,)  Tableau  Methodique  des  Especes  Minerales.  8vo. 
Paris,  1806-1813. 

Bournon,  (Comte  de,)  Catalogue  de  sa  collection  Mineralogique.  8vo. 
with  4to.  plates.  1813. 

Mawe,  (John,)  A  Treatise  on  Diamonds  and  Precious  Stones,  in- 
cluding their  History,  Natural  and  Commercial.  To  which  is 
added  some  account  of  the  best  method  of  cutting  and  polishing 
them.  8vo.  London,  1813. 

Brewster,  (Sir  David,)  On  the  Optical  Properties  of  Sulfuret  of  Car- 
bon, etc.,  with  Inferences  respecting  the  Structure  of  Doubly-re- 
fracting Crystals.  Fol.  Edinb.  1814. 

Davy,  (Sir  Humphry,)  Prof,  of  Chem.,  etc.,  etc.,  Some  Experiments 
on  the  Combustion  of  the  Diamond  and  other  Carbonaceous  Sub- 
stances. Phil.  Tram.  p.  557.  1814. 

Aiken,  (Arthur,)  Manual  of  Mineralogy.    8vo.    London,  1814. 

Allan,  Mineralogical  Nomenclature.     8vo.     London,  1814. 

Gravenhorst,(J.L.C.,)  Handbuchder  Anorganognosie.  8vo.  Leipzig, 
1815. 

Berzelius,  (J.  J.,)  Versuch  durch  Anwendung  der  elektrisch  chemis- 
chen  Theorie  und  der  chemischen  Verhaltnisslehre,  ein  rein  wis- 
eenchaftliches  System  der  Mineralogie  zu  begriinden.  Aus  dem 
Schwed  von  Dr.  A.  F.  Gehlen.  8vo.  Niirnberg,  1815. 

*Aikin,  (A.,)  Manual  of  Mineralogy.    12mo.    Philadelphia,  1815. 

Bournon,  (C.  de,)  A  Descriptive  Catalogue  of  Diamonds  in  the  Cabi- 
net of  Sir  Abraham  Hume.  4to.  London,  1815. 

Brewster,  (Sir  David,)  On  a  New  Optical  and  Mineralogical  Property 
of  Calcareous  Spar.  4to.  Edinb.  1815. 

Hauy,  Observations  sur  les  Tourmalines,  particulierement  sur  celles 
qui  se  trouvent  dans  les  Etats-TJnis.  Mem.  du  Mus.  Paris,  1815. 

John,  (J.  F.,)  Naturgeschichte  des  Succins,  oder  des  sogenannten 
Bernsteins.  8w>.  Koln,  1816. 

Swedenstierna,  (E.  T.,)  An  Account  of  the  Swedish  Corundum,  from 
Gellivara,  in  Lapland.  Geol.  Trans,  iii.  415.  1816. 

Svedenstjerna,  (E.  Th.,)  Ueber  den  Korund  zu  Gellivara  in  Lapland, 
ubersetzt  von  Dr.  Hessel.  Leonh.  Taschenb.  Frankfurt-a.-N.  1816. 

Berzelius,  (J.  J.,)  Neues  System  der  Mineralogie,  aus  dem  Schwedis- 
chen  von  Dr.  Gmelin  und  Pfaff.  8vo.  Nurnberg,  1816. 


*  Reprinted  foreign  works  arc  indicated  by  an  asterisk. 


482  APPENDIX. 

Tondi,  Element!  di  Orittognosia.     2  vols.     8vo.    Napoli,  1817. 

Haiiy,  (L'Abbe,)  Trait  e  des  caracteres  physique  des  pierres.  8vo. 
figs.  Paris,  1817. 

Sowerby,  Britisli  Mineralogy.    8vo.    London,  1802-1817. 

Leonhard,  (C.  C.,)  R.  F.  Menz,  und  J.  H.  Kopp,  Systematisch-Tabel- 
larische  Uebersiclit  und  Characteristik  der  Mineralkorper.  2  vols. 
Fol.  Frankfort,  1806 ;  2d  edit.  1817. 

*Phillips,  (Wm.,)  Outlines  of  Mineralogy  and  Geology.  12mo.  New- 
York,  1817. 

Zappe,  Mineralogische  Abliandlungen.     Wien,  1817. 

Haiiy,  (Rene  Just.,)  Traite  des  Caracteres  physiques  des  Pierres  pre- 
cieuses,  pour  servir  a  leur  determination  lorsqu'elles  sont  taillees. 
8vo.  Paris,  1817. 

Brewster,  (Sir  David,  LL.  D.,F.R.  S.  L.etc,,)  On  the  Optical  Proper- 
ties of  Muriate  of  Soda,  Fluate  of  Lime,  and  the  Diamond,  as  ex- 
hibited in  their  action  upon  Polarized  Light.  Phil.  Trans,  viii. 
.  157.  1817. 

Brewster,  (Sir  David,)  t)n  the  Effects  of  Compression  and  Dilatation 
altering  the  Polarizing  Structure  of  Doubly-refracting  Crystals. 
4to.  Edirib.  1818. 

Carton,  (J.,)  Englischer  Juwelier,  Kenntniss,  Werthund  Preisschat- 
zung  aller  Edelsteine,  Perlen  und  Corallen,  ins  Deut.  iibersetzt 
nach  der  10  ed.  12mo.  Ordtz,  1818. 

Fisher,  (G.  de  Waldheim,)  Essai  sur  la  Pellegrina,  ou  la  Perde  In- 
comparable des  freresZozima.  P amp.  Hist.  Nat.  8vo.  Moscou, 
1818. 

Teifascite,  (Ahmed,)  Fior  di  Pensieri  sulle  Pietre  Preziose,  opera 
stampata  nel  suo  originale  Arabo  di  Ant.  RainSri.  4to.  Firenze, 
1818. 

Jameson,  (Robert,)  System  of  Mineralogy.  2  vols.  pi.  8vo.  Edin- 
&wr^,1804;  2ded.  1816;  3d  ed.  1818. 

Hoffmann,  (C.  A.  E.,)  Handbuch  der  Mineralogie  mit  Fortsetzung  von 
A.  Breithaupt.  4  vols.  Freylerg,  1811-1818. 

^Phillips,  (Wm.,)  Elementary  Introduction  to  the  Knowledge  of 
Mineralogy,  with  notes  and  additions  on  American  Articles,  by 
Samuel  L.  Mitchijl.  12mo.  New-York,  1818. 

Dana,  (James  Freeman,)  Outlines  of  the  Mineralogy  and  Geology  of 
Boston  and  its  environs.  8vo.  Boston,  1818.  • 

*Thomson,  (Thomas,)  System  of  Chemistry,  in  4  vols.  Svo.,  the  3d 
containing  a  Treatise  on  Mineralogy.  Edited  by  Thomas  Cooper, 
from  the  5th  London  edition.  PMladelphia,  1818. 


APPENDIX.  483 

Bakewell,  (R.,)  Introduction  to  Mineralogy.    8vo.  London,  1819. 

Schoolcraft,  (Henry  R.,)  A  view  of  the  Lead  Mines  of  Missouri, 
including  observations  on  the  Mineralogy,  Geology,  Geography, 
&c.,  of  Missouri  and  Arkansaw,  and  other  portions  of  the  Western 
Country.  2  plates,  300  pp.  8vo.  New-York,  1819. 

Fladung,  Versuch  iiber  die  Kennzeichen  der  Edelsteine  und  deren 
vortheilhaftesten  Sclinitt.  Pesth,  1819. 

Brochant  de  Villiers,  (A.  J.  M.,)  Sur  la  cristallisation  geometrique- 
ment  et  physiquement  consideree.  With  numerous  plates.  8vo. 
Strasburg,  1819. 

Frischholz,  (J.,)  Lehrbuch  der  Steinschneidekunst,  fur  Steinschneider, 
Graveurs,  etc.,  und  jedens  welcher  sich  iiber  die  Veredlung  der 
Steine  zu  unterrichten  wiinscht.  Mvnchen,  1820. 

Harris,  (Thaddeus  M.,)  The  Natural  History  -of  the  Bible,  or  a 
description  of  all  the  quadrupeds,  birds,  fishes,  &c.,  precious  stones, 
&c.,  mentioned  in  the  Bible.  476  pp.  8vo.  Boston,  1820. 

Hausmann,  (J.  F.  L.,)  Untersuchungen  iiber  die  Formen  der  leblosen 
Natur  Ir.  Bd.  4to.  mit  vielen  Kupfern.  Gottingen,  1821. 

Mohs,  (Friederich,)  Die  Charaktere  der  Classen,  Ordnungen,  Gesch- 
lechten  und  Arten,  oder  die  Charakteristik  der  naturhistorischen 
Mineral-systems.  8vo.  Dresden,  1821. 

Brard,  (C.  P.,)  Mineralogie  appliquee  aux  arts.  3  vols.  8vo.  Paris,  1821. 

Berzelius,  (J.  J.,)  Von  der  Anwendung  des  Lothrohrs  in  der  Chemie 
und  Mineralogie  ;  Aus  der  Handschrift  ubersetzt  von  Heinr.  Rose. 
8vo.  Number g,  1821. 

Berzelius,  (J.  J.,)  The  same,  translated  by  J.  G.  Children.  8vo.  3 
pi.  London,  1822. 

Kick,  (Z.,)  Tentamen  JVIineralogicum,  seu  Mineralium  nova  distri- 
butio  in  classes,  ordines,  genera,  &c.  8vo.  BruxeUes,  1821. 

Koratz,  (Michel,)  Lexicon  Mineralogicum  enneaglottum.    8vo.   Pest. 

.  1821. 

Haiiy,  (L'Abbe,)  Traite  de  CrystaUographie.  2  vols.  8vo.   Perns,  1822. 

Haiiy,  (L'Abbe,)  Traite  de  Mineralogie.    4  vols.  8vo.    Paris,  1822. 

Cleaveland,  (Parker,)  Elementary  Treatise  on  Mineralogy  and  Ge- 
ology. 670  pp.  8vo.  Boston,  1816 ;  2d  edit,  in  2  vols.  8vo.  Bos- 
ton, 1822. 

*Lowry,  (Delvalle,)  Conversations  on  Mineralogy  and  Geology. 
Philadelphia,  1822. 

Blumhof,  (J.  C.,)  Lehrbuch  der  Lithurgik.    Frankfurt,  1822. 

Cohen,  (M.,)  Beschreibendes  Verzeichniss  einer  Sammlung  von  Dia- 
manten.  Wien,  1822. 


484  APPENDIX. 

Mackenzie,  (Sir  G.  S.,)  On  tlie  Formation  of  Chalcedony.   4ta   PMl. 

Trans.    London,  1832. 
Partsch,  (P.,)  Besclireibendes  Verzeichniss  einer  Sammlung  von 

Diamenten  und  der  zur  Bearbeitung  derselben  nothwendigen  Ap- 

parate,  etc.     Wien,  1822. 

Neumann,  Beitrage  zur  Kristallonomie.     8vo.    Berlin,  1823. 
Kosk,  (M.  F.,)  Beitrage  zur  Kenntniss  krys  tallin  Huttenproducte. 

8vo.     Gdttingen,  1823. 
Breithaupt,*(A.,)  Vollstandige  Charakteristik  des  Mineral-systems. 

8vo.    Dresden,  1823. 

Renier,  (S.  A.,)  Element!  di  Mineralogia.    8vo.    Padua,  1823. 
Phillips,  (Wm.,)  An  elementary  introduction  to  the  knowledge  of 

Mineralogy.    8vo.    London,  1823. 

Bellerinan,  (J.  J.,)  Die  Urim  und  Thummin.     Berlin,  1824. 
Glocker,  (Ernst  Friedrich,)  De  Gemmis  Plinii,  imprimis  de  Topazio. 

8vo.     Vratislaviai  (Breslau,)  1824. 
Brongniart,  (Alex.,)  Introduction  a  la  Mineralogie.    8vo.    Paris, 

1801 ;  2d  edit,  in  1824. 
Brard,  (C.  P.,)  Manuel  du  Mineralogiste.    12mo.    Paris,  1808  ;  3d 

edit.  1824. 
Steffens,  Vollstandiges  Handbuch  der  Oryktognosie.    4  vols.  8vo. 

Halle,  1811-1824. 
Stchegloff,  (N.,)  Mineralpguia  po  sistemie  Gospodinda  Haiiy.     2 

vols.  8vo.    St.  Petersburg,  1824. 
Webster,  Catalogue  of  Minerals  in  .the  State  of  New-York.    12mo. 

Albany,  1824. 

Hall,  (Frederick,)  Catalogue  of  Minerals  found  in  the  State  of  Ver- 
mont, and  in  the  adjacent  States.    44  pp.  8vo.    Hartford,  1824. 
Robinson,  (Samuel,)  Catalogue  of  American  Minerals,  with  their 

localities}  arranged  in  the  order  of  the   States.     8vo.  316  pp. 

Boston,  1825. 
Haidinger,  (Wm.,)  Treatise  on  Mineralogy,  or  the  Natural  History 

of  the  Mineral  Kingdom ;  translated  from  the  German  of  Mohs. 

3  vols.  8vo.    Edinburgh,  1825. 
Monticelli  and  Covelli,  Atlaute  della  Mineralogia  Vesuviana.    19  pi. 

Napoli,  1825. 
Marx,  (Dr.  C.  M.,)  Geschichte  der  Krystallkunde.     8vo.     Carlsrulie 

und  Baden,  1825. 
Ragoumovsky,  (Greg.  Comte  de,)  Distribution  Technique  des  Pierres 

precieuses,  avec  leurs  Caracteres  distinctifs.    8vo.     Vienne,  1825. 


APPENDIX.  485 

Rose,  (G.,)  Ueber  den  Felspath,  Labrador,  etc.,  Gilbert,  Ann.  Leipzig, 

1826. 
Leonhard,  (C.  C.,)  Handbnch  der  Oryctognosie.     8vo.   Heidelberg, 

1821  ;  2d  edit.  1826. 
Phillips,  (Wm.,)  Outlines  of  Mineralogy  and  Geology.    3d  edit.  8vo. 

London,  1818 ;  4th  edit.  1826. 
Naumann,  (G.  FT.,)  Entwurf  der  Lithurgik  oder    okonomischen 

Mineralogie.    8vo.    Leipzig,  1826. 

Rau,  (Ambros,)  Lehrbuch  der  Mineralogie.    8vo.     Wurzberg,  1826. 
Girardin  et  Lecoq,  Elemens  de  Mineralogie  appliquee  aux  science 

chimique.    2vols.    8ro.pl.    Paris,  1826. 
Drapiez,  Mineralogie  Usuelle,  504  pp.  12mo.     Paris,  1826. 
Blum,  (J.  R.,)  Verzeichniss  der  geschnittenen  Steine  indem  Konigl. 

Museum  zu  Berlin.    8vo.    Berlin,  1827. 
Del  Rio,  (Don  Andres  Manuel,)  Nuevo  sistema  M  nerale.     Mexico, 

1827.  •-,> 

Bredsdorf,  (J.  H.,)  De  notione  speciei  in  regno  minerali.     104  pp. 

12mo.     Copenhagen,  1827. 
Desnos,(J.  O.,)  Precis  de  Mineralogie  Moderne.    2  vols.    32mo.pl. 

formant20  et  21  livr.  de  TEncyclopedique  portative.     Paris,  1827. 
Glocker,  (Dr.,)  Grundriss  der  Mineralogie.     8vo.    Bredau,  1827. 
Bernhardi,  Beitrage  zur  Kenntniss  der  Cristallformen.      Erfurt 

1827. 
Comstock,  (J.  L.,)  Elements  of  Mineralogy,  adapted  to  the  use  of 

Seminaries  and  private  students.    Ixxvi.  and  338  pp.    8vo.     Bos- 
ton, 1827  ;  2d  edit.    12mo. 

Beumenberger,  (J.  G.,)  Der  Volkommene  Juwelier.     Weimar,  1828. 
Corsi,  (Faust,)  Delle  Piedre  antiche  libri  quattro.     Roma,  1828. 
Fladung,  (J.  A.  F.,)  Edelsteinkunde.    Sm.  8vo.     Wien,  1828. 
Hausmann,  (J.  F.  L.,)  Handbuch  der   Mineralogie.  3  vols.    8vo. 

Gottingen,  1813 ;  2d  edit.  1828. 
Breithaupt,  (A.,)  Physiotegie  der  Unorganischen  Natur.     8vo.  pi. 

Dresden,  1828. 
Blondeau,  Manuel  do  Mineralogie.    18mo.     Paris,  1825 ;  2d  edit. 

1828. 

Naumann,  (C.  Fr.,)  Lehrbuch  der  Mineralogie.    8vo.    Berlin,  1828. 
Freisleben,  (J.  Ch.,)  Magazin  fur  die  Orictographie  von  sachsen. 

8vo.    Freib&rg,  1828. 
Ermann,  Beitrage  zur  Monographie  des  Marekasit,  Turmalin  und 

Brasilianischen  Topas.    From  the  works  of  the  Berliner  Akad. 

4to.    Berlin,  1829. 


486  APPENDIX. 

Breithaupt,  (A.,)  Das  Gesclileclit  der  Rhomboedrischen  Turrnaline. 
Schweizzers  Jahrbmh  fur  Chym.  und  Phys.  8vo.  1829. 

Glocker,  (Dr.,)  Uebersiclit  der  Krystallisations-systeme,  etc.  48  pp. 
4tb.  Breslau,  1829. 

Glocker,  (Dr.,)  Handbuch  der  Mineralogie  fiir  Vorlesungen  und  zum 
Privategebrauch  bestimmt.  1829. 

Grasman,  (J.  Gunter,)  Zur  physischen  Krystallonomie,  und  geomet- 
rischen  Combinationslehre.  8vo.  184  pp.  3  pi.  Stettin,  1829. 

Frankenheim,  (M.  L.,)  De  Cristallorum  cohaesipne.    Breslau,  1829. 

Haidinger,  (Wm.,)  Anfangsgrunde  der  Mineralogie.  15  pi.  Leipzig, 
1829. 

Finder,  De  Adamante  Commentatio  Antiquaria.     Berlin,  1829. 

Macauley,  (James,)  A  sketch  of  the  Geology  and  Mineralogy  of  the 
State  of  New-York,  pp.  281-362,  in  a  work  entitled,  "  The  Na- 
tural, Statistical  and  Civil  History  of  the  State  of  New- York,  by 

•  James  Macauley."    3  vols.   8vo.    New-  York,  1829. 

Engelhardt,  (Ab.  von,)  Die  Lagerstatte  der  Diamanten  im  Ural- 
Gebirge.  4to.  Riga,  1830. 

Lancon,  (H.,)  L'Art  du  Lapidaire.    Paris,  1830. 

Schulze,  (H.,)  Practisches  Handbuch  der  Juwelierkunst  und  Edel- 
steinkunde.  Quedlinburg  und  Leipzig,  1830. 

Vettermann,  (A.,)  Kurze  Abhandlung  iiber  einige  der  vorziiglichsten 

.  Classen  der  Buntsn  oder  Gefarbten  Edelsteine.  8vo.  Dresden, 
1830. 

Beudant,  (F.  S.,)  Trait6  elementaire  de  Mineralogie.  8vo.  Plates. 
Paris,  1834  ;  2d  edit,  in  2  vols.  8vo.  1830. 

Naumann,  (C.  Fr.,)  Grundriss  der  Kystallographie.  8vo.  Leipzig, 
1826  ;  2d  edit.  2  vols.  1830. 

Glocker,  (Dr.,)  Handbuch  der  Mineralogie.  2  vols.  8vo.  pi.  Nurn- 
berg,  1831. 

Kobell,  (Frantz  von,)  Charakteristik  der  Mineralien.  Nurriberg,. 
1831.  • 

Heseell,  Crystallometrie.    Leipzig,  1831. 

Kupffer,  Handbuch  der  rechnenden  Kristallonomie.  4to.  pi.  St. 
Petersburg,  1831. 

Karsten,  (Dr.  C.  J.  B.,)  System  der  Mineralogie  geschichtlich  statis- 
tisch,  theoretisch  und  technisch.  5  vols.  8vo.  and  royal  folio  atlas, 
containing  51  plates.  Berlin,  1831. 

Baldwin,  (Ebenezer,)  Annals  of  Yale  College,  in  New-Haven,  Con- 
necticut. 8vo.  New-Haven,  1831.  Contains  a  sketch  of  the  Ge- 
ology and  Mineralogy  of  the  vicinity  of  Yale  College. 


APPENDIX.  487 

Proposals  of  the  Phenix  Mining  Company,  with  a  statement  of  the 

History  and  Character  of  their  Mines  in  Granby,  Conn.    30  pp. 

8vo.    New-York,  1831. 
Abich,  (H.,)  De  Spinello,  dissert,  inaug.  chem.    8vo.     Berolini, 

1831. 
Parrot^Notices  sur  les  Diamans  de  1'Oural.    4to.    Mem.  de  I'Acad. 

Imp.9  St.  Petersburg,  1832. 
Walchner,  Handbuch  der  gesammte  Mineralogie.    1104  pp.  8vo. 

Carlsruhe,  1832. 
Emmons,  (Ebenezer,)  Manual  of  Mineralogy  and  Geology.    230  pp. 

12mo.    Albany,  1826  ;  2d  edit.  299  pp.  12mo.  Albany,  1832. 
Jackson,  (C.  T.,)  and  Francis  Alger,  Remarks  on  the  Mineralogy  of 

Nova  Scotia.    1  pi.  115  pp.  8vo.     Cambridge,  Mass.,  1832. 
Del  Rio,  (C.  Andres,)  Elementos  de  Oryctognosia. '   8vo.    Philadel- 
phia, 1832. 
Mohs,  (Friederich,)  Der  Naturgeschichte  des  Mineralreichs.    Wien, 

1832. 
Brard,  (C.  P.,)  .Description  historique  de  sa  collection  de  Mineralogie 

appliquee  aux  arts.    8vo.    Paris,  1833. 
Kobell,  (Frantz  von,)  Tafeln  zur  Bestimmung  der  Mineralien,  etc. 

4to.    Munich,  1833. 
Presl,  (M.  K.  B.,)  Anleitung  zum  Selbststudium  der  Oryctognosie. 

8vo.    Prague,  1833. 
Catullo,  Element!  de  Mineralogia  applicata  alia  medicina  e  alia  far- 

macia.    2  vols.  8vo.    Padua,  1833. 
Rose,  (M.  Gustav,)  Elemente  der  Krystallographie.    8vo.    10  pi. 

Berlin,  1833. 

Uhde,  Versuch  einer  genetischen  Entwickelung,  &c.    A  Philoso- 
phical Essay  on  the  Mechanical  Laws  of  Crystallization.  8vo.  4  pi. 

Breme,  1833. 
Prestel,  (A.  E.,)  Anleitung  zur  perspective  Entwerfung,  &c.     On  the 

Perspective  projection  of  Crystalline  forms.    8vo.  pi.     Gottingen, 

1833. 
Welsh,  (Jane  Kilby,)  Familiar  Lessons  in  Mineralogy  and  Geology, 

designed  for  the  use  of  young  persons  and  Lyceums.    2  vols. 

12mo.    Boston,  1833. 
Hitchcock,  (Edward,)  Report  on  the  Geology,  Mineralogy,  Botany 

and  Zoology  of  Massachusetts,  made  and  published  by  order  of 

that  State.    700  pp.  8vo.    Amherst,  1833. 
Cairne,  (A.,)  La  Science  des  Pierres  precieuses  appliquee  aux  arts. 

Paris,  1833. 


488  APPENDIX. 

Blum,  (Dr.  Reinliart,)  Die  Schmuckstejne.  Heidelberg,  1828,  und 
Taschenbuch  der  Edelsteinkunde.  12mo.  Stutgart,  1834. 

Burch,  (A.,)  Handbuch  fiir  Juweliere.     Weimar,  1834. 

Ilartmann,  (C.  F.  A.,)  Mineralogie.  8vo.  pi.  llmenau,  1828  ;  also 
in  1834.  9 

Hartmann,  (C.  F.  A.,)  Repertorium  der  Mineralogie.  8vo.  pi,  Leipzig, 
1834. 

Allan,  (Robert,)  A  Manual  of  Mineralogy.  350  pp.  8vo.  Edinburgh, 
1834. 

Suckow,  (M.  G.,)  Grundriss  der  Mineralogie.  8vo.   Darmstadt,  1834. 

Mather,  (William  W.,)  Sketch  of  the  Geology  and  Mineralogy  of 
New-London  and  Windham  Counties,  in  Connecticut.  36  pp%  8vo. 
with  a  map.  Norwich,  1834. 

Moore,  (N.  F.,)  Ancient  Mineralogy,  or  an  Inquiry  respecting  Min- 
eral Substances  mentioned  by  the  Ancients.  192  pp.  12mo.  New- 
York,  1834. 

Porter,  (Jacob,)  Topographical  Description  and  Historical  Sketch  of 
Plainfield,  in  Massachusetts.  44  pp.  8vo.  Greenfield,  1834. 

Hartmann,  (C.  F.  A.,)  Grundziige  der  Mineralogie  und  Geologic. 
8vo.  Nwrnberg,  1835. 

Richard,  (A.,)  Precis  elementaire  de  Mineralogie.  8vo.  pi.  Paris, 
1835. 

Frankenheim,  (M.  .L.,)  Die  Lehre  von  der  Cohasion,  umfassend  die 
Elasticitat  der  Gase,  die  Elasticitat  und  Coharenz  der  flussigeii 
und  sesten  Korper  und  die  Krystallkunde.  502  pp.  8vo.  Breslau, 
1835. 

Necker,  Le  regne  mineral  ramene  aux  methodes  de  1'histoire 
naturelle.  2  vols.  in  8vo.  of  above  400  pages  each.  Paris,  1835. 

Thomson,  (Thomas,)  Geology  and  Mineralogy,  forming  the  third 
portion,  or  the  fourth  and  fifth  volumes  of  his  System  of  Chemistry. 
2  vols.  8vo.  London,  1835. 

Shepard,  (Charles  Upham,)  Treatise  on  Mineralogy,  1st  part  one  vol. 
12mo.  New-Haven,  1832.  2d  part  consisting  of  descriptions  of  the 
species,  and  tables  illustrative  of  their  Natural  and  Chemical 
affinities.  2  vols.  12mo.  with^SOO  wood  cuts.  New-Haven,  1835. 

Kurr,  Grundziige  der  okonom-techischen  Mineralogie.     8vo.     1836. 

Hochsteller,  Populare  Mineralogie.     12  pi.     8vo.     1836. 

*Moffatt,  (J.  M.,)  Mineralogy  and  Crystallography  ;  pp.  236-298  of 
the  Scientific  Class  Book.  Reprinted  with  additions  from,  the 
London  edition,  by  Walter  R.  Johnson.  12mo.  Phttadel/phia, 
1836. 


APPENDIX.  489 

Gesner,  (Abraham,)  Remarks  on  the  Geology  and  Mineralogy  of 

Nova  Scotia.    8vo.    272  pp.    Halifax,  1837. 
Dowd,  (J.  A.,)  System  of  Mineralogy.    New-Haven,  1837. 
Feuchtwanger,  (Lewis,)  Treatise  on  Gems.    New-York,  1838. 
Hertz,  (B.,)  Catalogue  of  Mr.  Hope's  Collection  of  Pearls  and  Precious 

Stones,  systematically"  arranged  and  described.    4to.    London, 

1839. 
Rose,  (G.,)  De  Novis  quibusdam  Fossilibus  quae  in  montibus  Uraliis 

inveniuntur,  Chrysoberillum,  Uralium,  etc.    8vo.    Berobini,  1839. 
Blum,  (J.  R.,)  Lithurgik,  oder  Mineralien  und  Felsarten,  nach  ihrer 

Anwendung  in  Oekon.,  Artist,  und  Technischer  Hinsicht  system- 

atisch  abgehandelt.     Stutgart,  1840. 
Roy,  (C.  W.  van,)  Ansichten  iiber  Entstehung  und  Vorkommen  des 

Bernsteins,  so  wie  praktische  Mittheilungen  iiber  den  Werth  und 

die  Behandlung  desselben  als  Handelsware.    8vo.  Dantzig,  1840. 
Konneritz,  (L.  von,)  Mittheilung  mannichfaltiger  Versuche  Edel- 

steine  kunstgemass  zu  schleifen.     Weimar,  1841. 
Steinbeck,  Ueber  die  Bernstein-Gewinnung.    8vo.    Brandenburg, 

1841. 
Petzholdt,  (M.,)  Beitrage  zur  Naturgeschichte  des  Diamantes.    8vo. 

Dresden  und  Leipzig,  1843.        •  •- 
Transactions  of  the  Imperial  Russian  Mineralogical  Society  at  St. 

Petersburg,  1842. 

Ramdedsberg,  (C.  F.,)  Chemical  Mineralogy.    Berlin,  1843. 
Alger,  (Francis,)  Elementary  Treatise  on  Mineralogy,  by  William 

Phillips.    Boston,  1844. 
Bielhe,  (Von,)  Bernstein,  ein  gewichtiges  Naturproduct  des  Konig- 

reichs  Danemark.    8vo.    Hamburg,  1845. 
Haidinger,  (W.,)  Ueber  den  Pleochroismus  dee  Amethysts.    Natur- 

mssenschaftliche  Abhandlungen.     Wien,  1846. 
Priifer,  (V.,)  Ueber  die  Krytalfonn  der  Lazulith.     4to.     Natur- 

wissensch.  Abhand.    Wien,  1847. 
Goepert,  (H.  R.,)  Ueber  Pflanzenahnliche  Einschlusse  in  den  Chalce- 

donen.    8vo.    1848. 
Haidinger,    (W.,)    Ueber  den    Pleochroismus    des    Chrysoberylls. 

Berichte  iiber  Mittheilungen  von  Freunden  der  Naturwissenschaf- 

ten.    8vo.     Wien,  1848. 
Haidinger,  (W.,)  Ueber  eine  neue  Varietat  von  Amethyst.    Derik- 

8chHfLd.Kais.Akad.    4tov    Wien,  1849. 


490  APPENDIX. 

* 

Harting,  (P.,)  Description  d'un  Diamant  remarquable,  contenant'des 

crystaux.    Acad.  roy.  des  Sciences.    4to.    Amsterdam,  1850. 
Loew,  Ueber  den  Bernstein  und    die  Bernstein-Fauna.     Berlin, 

1850. 

Zerrenner,  (Dr.  Carl,)  De  Adamanti  Dissertatio.    Lipsice,  1850. 
Zerrenner,  (C.,)  Anleitung  zum  Diamanten.    Wasclien  aus  Seifenge- 

birge,  Ufer-und  Flusbett-Sand.    8vo.    Leipzig,  1851. 
Hindmarsli,  (R.,)  Precious  Stones,  being  an  account  of  the  Stones 

mentioned  in  the  Sacred  Scriptures.    8vo.    London,  1851. 
Booth,  Encyclopedia.    Philadelphia,  1852. 
Rose,  (G.,)  Das  Krystallo-Chemische  Mineral-system.    8vo.   Leipzig, 

1852. 
Haidinger,  (W.,)  Pleochroismus  und  Krystallstructur  des  Ame- 

thystes.    Sitzungsber.  der  Kais.  Akad.    8vo.     Wien,  1854. 
Fontenelle,  Nouveau  Manuel  Complet  du  Bijoutier.    8vo.    Paris, 

1855. 
Labarte,  (M.  Jules,)  Handbook  of  the  Arts  of  the  Middle  Ages  and 

Renaissance  as  applied  to  the  Decoration  of  Jewels,  Arms,  etc. 

8vo.    London,  1855. 
Schmidt,  (C.  J.,)  Das  Wichtigste  iiber  den  Opal  in  Allgemeinen  und 

iiber  sein  Vorkommen  in  Mahftsn  im  Besonderen.    Mittheil.  d.  k. 

k.  mdhr.  scJiles.  Gesellsch.    Brunn,  1855. 

Volger,  (G.  H.  O.,)  Versuch  einer  Monographic  des  Borazites.    Hano- 
ver, 1855. 
Volger,  (G.  H.  0.,)  Epidot  und  Granat,  Beobachtungen  iiber  das 

gegenseitige  Verhiiltniss  dieser  Krystalle.    4to.    Zurich,  1855. 
Kokscharow,  (Nic.  von,)  Ueber  die  russischen  Topase.    4to.     Mem. 

de  I' Acad.  Imp.    Petersbourg,  1856. 
Krause,  (T.  H.,)  Pyrgoteles,  oder  die  edeln  Steine  der  Alten  in 

Bereiche  der  Natur,  etc.    Halle,  1856. 
Loninser,  (Gust.,)  Die  Marmaroscher  Diamanten.    4to.    Presburg, 

1856. 
Ritter,  (C.,)  Der  Tu-(Yu-)stein,  d.  i.  der  Tu-chi  der  Chinesen,  Kasch 

der  Tiirken,  Yeschet  der  Perser,  oder  Jaspis  der  Alten,  sein  Fun- 

dort  in  Khotan,  sein  Verbrauch  und  Handel.    8vo.    Berlin,  1856. 
Ginanni,  (Fantuzzi  M.,)  Osservazioni  geognostiche  sul  Coloramento 

di  alcune  Pietre  e  sulla  formazione  di  un  Agata  nel  Museo  Ginanni 
di  Ravenna.    8vo.    1857. 

Mobius,  (K.,)  Die  echten  Perlen.    4to.    Hamburg,  1857. 
Barbot,  (Ch.,)  Traite  complet  des  Pierres  precieuses.    8vo.    Paris, 
1858. 


APPENDED  491 


V 


Haidinger,  (W.,)  Der  fiir  Diamant  oder  noch  Werthvolleree  aus- 
gegebene  Topas  des  Herrn  Dupoisat.  Sitzungsber.  der  Kais.  Akad. 
4to.  Wien,  1858. 

Rudolph,  (A.,)  Die  edeln  Metalle  und  Schmucksteine,  mit  37  Ta- 
beUen.  Breslau,  1858. " 

Scheerer,  (Th.,)  Ueber  den  Traversellit  und  seine  Begleiter  Pyrgom, 
Epidot,  Granat.  Ein  neuer  Beitrag  zur  Beantwortung  der  Pluton- 
ischen  Frage.  Bericht.  der  Kngl.  sdcJis.  GeseUsch.  8vo.  Leipzig, 
1858. 

Feuchtwanger,  (Dr.  L.,)  A  Popular  Treatise  on  Gems,  in  reference 
to  their  scientific  value,  etc.  8vo.  New-York,  1859. 

Hessh'ug,  (Th.  von,)  Die  Perlmuschel  und  ihre  Perlen.  8vo.  Leipzig, 
1859. 

Kluge,  Edelsteinkunde.    Leipzig,  1860. 

Pole,  (W.,)  Diamonds.    8vo.    Land.  Archaol.  Trans.   London,  1861. 

Pisani,  (J.,)  Sur  le  Grenat  octoedrique  de  1'Ile  d'Elbe.  4to.  Comptes 
rend,  de  VAcad.  des  Sciences.  Paris,  1862. 

Sotto,  (Js.,)  Le  Lapidaire  du  quatorzieme  Siecle.    8vo.    Wien,  1862. 

Zepharovitch,  (V.  v.,)  Der  Diamant,  ein  Popularer  Vortrag.  8vo. 
Gratz,  1862. 

Lacaze,  (Duthiers  H.,)  Histoire  Naturelle  du  Corail,  Organisation, 
Reproduction,  Peche  en  Algerie,  Industrie,  etc.  8vo.  Paris,  1864. 

Von  Kobell,  (Franz,)  Die  Mineralogie.    Leipzig,  1864. 

Madelung,  (A.,)  Die  Metamorphosen  von  Basalt  und  Chrysolith  von 
Hotzendorf  in  Mahren.  4to.  *  Jahrb.  d.  Geol.  Reichsanst.  Wien, 
1864. 

Partsch,  (P.,)  Catalogue  of  the  Geological  Cabinet  at  Vienna,  with 
a  Biographical  List  of  the  Works  treating  on  the  subjects  of  Ge- 
ology, Oryctology,  and  Palaeontology.  8vo.  Vienna,  1864. 

Emanuel,  (H.,)  Diamonds  and  Precious  Stones.    London,  1865. 

Annales  des  Mines.    Paris. 

Boetius,  (Anselmus,)  Tractatus  de  Lapidibus  et  Gemmis.     Var.  ed. 

Bondary,  (Jean  de  la  Taille  de,)  Blason  des  Pierres  precieuses. 

Bouillon,  (De  la  Grange,)  Analysis  of  the  Substance  known  by  the 
name  of  Turquoise.  Nick.  Journ.  xxi.  182. 

Cardanus,  (Hieronymus,)  De  Lapidibus  preciosis ;  also  de  Subtilitate. 
Var.  ed. 

Guyton-Morveau,  (B.  L.,)  Account  of  certain  Experiments  and  Infer- 
ences respecting  the  combustion  of  the  Diamond  and  the  Nature 
of  its  composition.  Nich.  Journ.  iii.  298. 

Kohler,  (H.  K.  A.  von,)  Kleine  Abhandlungen  zur  Gemmenkunde. 


492  .APPENDIX. 

Lucretius,  De  Rerum  Natura.     Var.  ed. 

Mortimer,  (Cromwell,  M.  D.,)  Remarks  on  the  Precious  Stone  called 

Turquois.    Phil.  Trans.  Abr.  viii.  324.    London. 
Phillips,  Mineralogy.     Var.  ed. 
Philostratus,  De  Vita  Apollonii.     Var.  ed. 
Vauquelin,  (Citizen,)  Information  respecting  the  earth  of  the  Beryl. 

Mch.Journ.u.  393. 
Vauquelin,  (Citizen,)  Analysis  of  the  Chrysolite  of  the  Jewellers, 

proving  it  to  be  Phosphate  of  Lime.    Nich.  Journ.  ii.  414. 
Vauquelin,  (Citizen,)  Analysis  of  the  Aqua  Marine  or  Beryl,  etc. 

Nidi.  Journ.  ii.  358. 

Vega,  (Garcilaso  de  la,)  History  of  the  Incas.     Var.  ed. 
Wecker,  or  Weckerus,  Antidotae  speciales  de  Lapidibus  minus  pre- 

tiosis  alterantibus. 

Poggendorff's  Annalen  der  Physik  und  Chemie. 
Brooks  in  the  Encyclopedia  Metropolitain. 
Berzelius'  Annual  Reports. 

London,  Edinburgh  and  Dublin  Philosophical  Magazine. 
.  Jamieson's  New  Edinburgh  Journal  of  Science. 
Brewster's  Edinburgh  Journal  of  Science. 
Thomson's  Records  of  General  Science. 
Reports  of  the  British  Association. 
De  Ik  Beche's  Report. 
Silliman's  American  Journal  of  Science. 
Haiiy,  (L.  Abbe,)  Tableau  comparatif  des  resultas  de  la  Crestallo- 

graphie  et  de  1'analyse  chimique,  relativement  a  la  classification 

des  mineraux.    8vo.    Figs.    Paris. 

Kidd,  (J.,)  Outlines  of  Minerology.    2  vols.    8vo.     Oxford. 
Karsten's  Archiv  fur  Mineralogie.    8vo.    Berlin. 
Glocker,  Mineralogischen  Jahreshefte.    8vo.    Breslau. 
Hartmann,  Jahrbuch  der  Mineralogie,  Geologie,  &c.    8vo. 
Leonhard  und  Bronn,  Neues  Jahrbuch  fur  Mineralogie,  Geographie, 

Geologie  und  Petrefaktenkunde.    8vo. 


The  British  Museum,  containing  some  Ancient  Manuscripts  relating 
to  the  subject  : 

Galamazar,  Liber  vertutibus  Lapidum  Pretiosorum  quern  scripsit 
Galamazar,  Thesaurarius  Regis  Babylonie,  ipso  presenti  et  pre- 
cipiente.  Harleian  MSS.  8vo. 


APPENDIX.  493 

De  Lapidibus,  Avibus  et  Arboribus  Indiae,  Arabiae  et  AMcae.    Har- 

leian  M88.    8vo. 
Lapidum  Pretiosorum  usus  Magicus,  sive  de  Sigillis.    Harleian 

MS8.    8vo. 
Liber  Hermetis  tractans  de  15  Stellis  et  de  15  Lapidibus  et  de  15 

Herbis  et  de  15  Figuris.    Harleian  MSS.    8vo. 


494 


TABLE  OF  THE  DISTINGUISHING 


Name  and  Color. 

Lustre. 

Specific 
Gravity. 

Hardness. 

No.  in 
Scale  of 
Hard- 
ness. 

Composition. 

System  of 
Crystalliza- 
tion. 

DIAMOND. 

Adamantine  ; 

8-4  to  3  -6 

Scratches  all 

10. 

Pure  Carbon. 

Monometric 

White,   pink,    yellow, 
red,  blue,  green,  black, 

reflects 
prismatic 

other      pre- 
cious stones. 

or  cubical. 

orange,  brown,  opales- 

colors. 

cent. 

BOART. 

CARBONATE,  (compact 

None. 

massive  variety.) 

SAPPHIRE. 
•d  f    White,  blue,  violet. 

Vitreous; 
very  lively. 

3-9  to  4-2 

Scratched  by 
diamond  ; 

9 

Alumina,  .    .  9£'5 
Oxide  of 

Hexagonal 
or    rhom- 

o     RUBY,    pink,    red, 

scratches 

Iron,      .    .    1-0 

bohedral. 

w       violet-red. 

all  others. 

Lime,    ...    0'5 

«     TOPAZ,     Oriental. 

"*  j     yellow. 
|  '  AMETHYST,  Orien- 

.g        tal,  purple,  violet. 
•S     EMERALD,  Orien- 

-* 

Jtal,  green,  gener- 

.    ally  pale. 

CHRYSOBERYL,  or 
ORIENTAL    CHRYSO- 

Vitreous ; 
sometimes 

3-  to  8-8 

Scratched  by 
.  sapphire, 

8'5 

Alumina,  .    .  80'2 
Glucina,    .     .  19-8 

Trimetric  or 
rhombic. 

LITE. 
Bright    pale   -  green, 
greenish-yellbw,     red- 
dish-brown. 

pearly. 

etc.; 
scratches 
quartz 
readily. 

(Trace  of  Per-ox- 
ide  of   Iron,  of 
Oxide   of  Lead 

prismatic. 

ALEXANDRITE,  when 

and  Copper,  de- 

exhibiting  a   reddish, 

pending  on  color 

transmittent  light. 
CYMOPHANE,  or 

and  locality.) 

CHRYSOBERYL  CAT'S 

EYE,  when  showing  an 

opalescence  like  a  cat's 

eye. 

SPINEL. 

Vitreous 

3-8 

Scratched  by 

8 

1 

Alumina,     .  69'01 

Monometrio 

Dark-red,  white,  blue, 

sapphire  ; 

Magnesia,    .  26-21 

or  cubical. 

green. 

scratches 

Protoxide 

PLEONASTE  or  CEY- 

quartz 

of  Iron,     .    0-71 

LANITE,  black. 

readily. 

Silica,      .    .    2-02 

RUBICELLE,  orange. 

Oxide  of 

BALAS  RUBY,  rose-red. 

Chrome,  .    1-10 

TOPAZ. 

Vitreous. 

3'5to3-6 

Scratched  by 

8 

Silica,           .  34-01 

Trimetric  or 

White,    greenish,   yel- 

sapphire ; 

Alumina,     .  58  -88 

rhombic. 

low,  orange,  cinnamon, 

scratches 

Fluorine,     .  15-06 

bluish,  pink. 

quartz 

Traces  of  metallic 

easily. 

oxides. 

495 


CHARACTERISTICS   OF  GEMS. 


Form  of  Crystal. 

Refraction. 

Refractive 
Index. 

Disper- 
sive 
Power. 

Electric 
Properties 

Fusibility. 

Diaphaneity. 

Cube, 
Octahedron, 
Rhombic  dodecahedron, 
Tetrahedron, 
Hexa-octahedron. 

Single. 

White,  2-455 
Brown,  2-487 

0-88 

Acquires  posi- 
tive electri- 
city by  fric- 
tion ;  non- 
conductor of 
electricity. 

Infusible  ; 
volatilized 
by     long- 
continued 
heat. 

Transparent 
and  trans- 
lucent ; 
Carbonate 
opaque. 

Hexagonal  prism  ;    often 
pointed  at  each  end. 

Double,  in  a 
small    de- 
gree. 

1-765 

0-026 

Acquires  elec- 
tricity by 
friction,  and 
retains  it 
several 
hours. 

.  •  •  * 

Transparent. 

In  flat  hexagonal  crystals  ; 
generally  in  rolled  peb- 
bles. 

Double. 

1-760 

0-033 

Acquires  elec- 
tricity by 
friction,  and 
retains  it 
several 
hours. 

Infusible, 
alone. 

Transparent 
and  semi- 
transpa- 
rent. 

Octahedron, 
Khombic  dodecahedral 
octahedron, 
Tri-octahedron. 

Single. 

1-755  to 
1-810 

0-040 

.... 

infusible, 
alone. 

Transparent, 
translucent. 

*  Eight-rhombic  prism, 
Octahedral  rhombic  prism. 

Double,  in  a 
slight  de- 
gree. 

1-635 

0-025 

Acquires  elec- 
tricity by 
friction  and 
heat. 

Infusible. 

Transparent, 
translucent 

496 
TABLE  OF  THE  DISTINGUISHING 


'  Name  and<3olor. 

Lustre^. 

Specific 
Gravity. 

Hardness. 

No.  in 
Scale  of 
Hard- 
ness. 

Composition. 

System  op 
Crystallize 
tion.    -  ] 

EMERALD. 

Vitreous. 

2-67  to  2-75 

Scratched  by 

7  '5  to  8- 

Silica,      .    .  68-50 

Hexagonal 

Fine  green. 

spinel  ; 

Alumina,     .  15'75 

or  rhom-' 

BERYL,  or  AQUAMA- 

scratching 

Glucina,     -.  12'50 

bohedral.^ 

RINE,  pale  sea-green, 

quartz, 

Oxide  of 

blue,    white,     yellow, 

(specimens 

Iron,    .     .    1-00 

rarely  pink. 

vary.) 

Lime,      .    .    0'25 

HYACINTH,  or 

Vitreous, 

4-07  to  4-70 

Scratches 

7-5 

Silica,      .     .    33-0 

Diometricoi 

JACINTH,      brownish- 

(almost  ad- 

quartz 

Zircon  ia,      .     66.  S 

square 

yellow,    brownish-red. 

amantine.) 

slightly. 

1'eroxide  of 

prismatic; 

cinnamon. 

Iron,     .    .    O'l" 

pyramida 

JARGOON,     various 

shades  of  green,  yel- 

low, white,  brown. 

GARNET. 

Vitreous,  in- 

3 5  to  4-3 

Scratches 

6-5  to  7  '5 

Silica.      .    .  38-25 

Monometric 

ALMANDINE,  vio- 
-o        let-red. 

clining     to 
resinous. 

quartz 
slightly. 

Alumina.      .  19-35 
Lied  Oxide 

or  cubical 

o     CARBUNCLE,  red. 

of  Iron,    .    7  '83 

o>        brownish. 

Lime,       .    .  81-75 

"CINNAMON- 

Magnesia,    .    240 

STONE,  white, 

Protoxide 

~"       yellow,  orange. 
|     PYROPE,     vermil- 

of  Man- 
ganese,    .     0'5U 

i;         ion    or    Bohemian 

garnet. 

TOURMALINE. 
Green,  red,  brown,  yel- 

Vitreous. 

2  99  to  8  -3 

Scratches 
quartz 

7-  to  7  -5 

Fluorine,     .    2  '28 
Silica,      .    .  38-85 

Elexagonal 
or  rhom- 

low,  blue,  black,  some- 

slightly. 

Boracic  Acid,  S'25 

bohedral. 

times  white. 

Alumina,     .  81  '82 

Red  Oxide 

of  Iron,    .     1-27 

Magnesia,    .  13'89 

Lime,       .    .    1-60 

" 
£ 

Soda,  .    .    .     1-28 

Potash,    .    .    0-26 

QUARTZ,  -r 

Vitreous. 

2-65 

Scratches     ' 

7 

Silica.      .    .  99-87 

Hexagonal 

ROCK  CRYSTAL, 

glass.  • 

Alumina,     . 

or  rhora- 

white. 

bohedral. 

AMETHYST,  violet. 

Amethyst,    . 

CAIRNGORM,     ytllow. 

brown. 

Silica,      .     .  97  -5f 

• 

CHRYSO  PRASE,      fine 

Alumina.     .    0"25 

apple-green. 

Red  Oxide 

CAT'S  EYE,  ha  vlngchu- 

of  Iron,"    .     0-50 

toyaxt  reflection. 

Oxide  of 

PLASMA,     deep     olive- 

Man- 

green. 

ganese,     .     0'25 

JASPER,    yellow,    red, 

green,  blnck,  brown. 

49' 


CHARACTERISTICS   OF   GEMS.— ( Continued.) 


Form  of  Crystal; 

• 
Refraction. 

Eefractire 
Index. 

Disper- 
sive 
Power. 

Electric 
Properties. 

Fusibility. 

Diaphaneity. 

Hexagonal  prism. 

Double, 
(very 
feeble.) 

1-585 

0-026 

Acquires  posi- 
tive electri- 
city by  fric- 

Slightly  fu 
sible     be- 
fore      the 

Transparent. 

tion. 

blowpipe. 

Long  square  prism, 
Short  square  pri>m. 
Long  square  octahedron. 
The  prisms  often    doubly 

Double,  in  a 
very  high 
degree,e- 
pecially  in 

1-990 

0-044 

Do.        do. 

In  fusible  be- 
fore     the 
blowpipe. 

Transparent 
to  opaque. 

• 

terminated  with  square 

the     Jar- 

pyramids. 

gonn       ol 

v_eylon. 

Rhombic  dodecahedron. 
Rhombic  «l»d  •••  uhrdral 

Simple. 

1-159 

0-088 

Do.        do. 

Fusible    be 
fore      the 

Transparent, 
opaque. 

cube. 

blowpipe. 

Trapezohedmn, 

II  exa-octa  hedron  . 

)btuse  rhombohedron, 
iexagonal  prisms. 

Double. 

1-625 

0-023 

Acquires  posi- 
tive and  neg- 

Fusible. 

From  trans- 
parent   to 

ative     elec- 

opaque. 

tricitv       by 

• 

friction  and 

• 

heat. 

lexagonal  prism, 
Bipvramidal,  dodecahe- 

Doable. 

1-549 

0-026 

Acquires  posi- 
tive electri- 

Infusible. 

Transparent 
and  trans- 

dfal. 

city  by  fric- 

lucent. 

tion. 

Many  varie- 

ties, nearly 

opaque.) 

498 


TABLE   OF  THE  DISTINGUISHING 


Name  and  Color. 

Lustre. 

Specific 
Gravity. 

Hardness. 

No.  in 
Scalp  of 
Hard- 
ness. 

Composition. 

System  of 
Crystalliza- 
tion. 

BLOODSTONE,      dark- 
green,  with  red  spots. 
CAENELION,   red, 
white,  yellow. 
AGATE,  various  colors. 
ONYX,    having    black, 
brown  and  white  layers. 
SARDONYX,     hav- 
ing  red  or  brownish 
and  white  layers. 
MOC  H  A-STONE,having 
infiltrated    Oxides    of 
Iron     or    Manganese, 
producing      dendritic 
appearances. 

Vitreous. 
Vitreous. 

Vitreous,  in- 
clining    to 
resinous. 

Pearly. 

8-3  to  S'  14 
2  -62  to  3- 

2'0  to  2-3 
2-5  to  2-7 

Scrafchedby 
quartz. 

Scratches 
glass 
feebly. 

Scratches 
glass 
slightly. 

Various. 

6-  to  7' 

6 

5-5  to  6-5 
2-5  to  3  -5 

Silica,      .    .  39-73 
Magnesia,    .  60'13 
Protoxide 
of  Iron,    .    9-19 
Oxide  of 
Nickel,     .    0-32 
Oxide  of 
Man- 
ganese,    .    0'09 
Alumina,     .    0'22 

Phos.  Acid,  .  27-84 
Alumina,     .  47*45 
Oxide  of 
Copper,    .    2-05 
Oxide  of 
Iron,     .     .'1-10 
Oxide  of 
Man- 
ganese,    .    0'50 
Phosphate 
of  Lime,    .    3'41 
Water,    .    .  18-18 

Silica,       .    .  91-32 
Water,     .    .    8-63 

Traces  of  mineral 
coloring-matter 

Carbonate           o: 
Lime,      organic 
matter. 

Tri  metric  or 
rhombic. 

None. 

None. 
None. 

CHRYSOLITE. 
PERIDOT,  olive-green. 
OLIVINE. 

TURQUOISE. 
Blue,  green,  white. 

OPAL. 
Colorless,  red,  white, 
green,  gray,  black,  yel- 
low. 
(Iridescent.) 

PEARL. 
White,    yellow,    pink, 
black,    violet,   brown, 
gray. 

499 


CHARACTERISTICS  OF  GEMS.— ( Continued.) 


Form  of  Crystal. 

Refraction. 

Refractive 
Index. 

Disper- 
sive 
Power. 

Electric 
Properties. 

Fusibility. 

Diaphaneity. 

• 

Generally  in  rolled  grains 
and  pebbles. 

Double. 

1-660 

1-088 

Acquires  elec- 
tricity      by 
friction. 

Infusible. 

Transparent 
and  trans- 
lucent 

None. 

.... 

.... 

.... 

None. 

Infusible. 

Opaque. 
Translucent 
at  edges. 

None. 

.... 

.... 

,-'>r?P> 

Infusible. 

Semi-trans- 
parent. 

None. 

None. 

None. 

None. 

None. 

Calcines  by 
moderate* 
heat. 

Opaque  ; 
sometimes 
semi-trans- 
parent. 

502  APPENDIX. 

The  value  of  stones  above  five  carats  is  not  attempted  to  be  given, 
as  it  is  impossible  to  fix  it  with  any  accuracy.  It  depends  entirely 
on  the  demand  for  any  particular  size  and  the  supply  in  the  market  ; 
it  remains  a  matter  of  negotiation  between  the  buyer  and  seller. 

When  a  Diamond  has  a  very  decided  color,  such  as  blue,  red, 
green,  &c.,  it  is  called  a  fancy  stone,  and  will  bring  a  most  exorbitant 
price.  A  stone  of  five  grains,  of  a  brilliant  emerald-green  color,  for 
which,  if  white,  not  more  than  £28  stg.  could  be  obtained,  has  been 
known  to  sell  for  £320  stg.  The  terms  first  water,  second  water, 
&c.,  mean  only  first  and  second  quality.  Diamonds,  when  perfect, 
should  be  clear  as  a  drop  of  the  purest  water,  and  they  are  described 
as  second  or  third  water  when  more  or  less  clear,  until  decidedly  yel- 
low or  brown,  when  they  are  termed  colored.  The  value  of  stones  of 
the  first  quality  of  a  less  weight  than  two  grains,  (half  a  carat,)  is, 
according  to  Mr.  Emanuel,  £10  stg.  per  carat  ;  the  second  quality, 
£8  stg.  ;  the  third,  £7  stg.  per  carat. 

The  plates  representing  the  sizes  of  the  Diamonds,  given  in  this 
Treatise,  are  drawn  from  nature  ;  still  it  is  quite  difficult  to  get  at 
the  actual  weight,  for  the  Diamond  cutters  of  the  present  day  turn 
their  attention  more  to  the  production  of  the  greatest  weight  from 
a  given  quantity  of  rough  Diamond,  than  to  the  production  of  per- 
fectly proportioned  stones,  for  which  reason  we  often  meet  with 
stones  weighing  three  carats,  whose  proper  weight,  if  reasonably 
spread,  should  be  two,  which  renders  them  less  valuable  and  not 
nearly  so  brilliant  as  one  of  two  carats  properly  cut  ;  any  over  or 
under  weight  only  detracts  from  its  beauty.  A  well  proportioned 
spread  Diamond  finds  more  amateurs  than  a  heavy  one.  At  present 
the  following  prices  may  be  quoted  for  Diamonds  in  gold  currency, 


*2  grains,  (half  a  carat,)  from  .........      $68  to    $75,  gold. 


1  carat,             "  ... 

110  to  140  " 

1-J-  "   (6  grains  )     "  . 

200  the  stone  " 

2  "   (8   "   )     " 

.  ..   400 

3  "   (12   "   ">     " 

.  .  .  1  200  to  1  400  " 

4  "  (16   "   )     "  . 

1  600  to  2  000  " 

6  "  (20   "   )     "  . 

3  000  to  4  000  " 

*  4  grains  are  equal  to  1  carat. 

151)6  carats       "       "1  ounce  troy  weight. 


APPENDIX.  503 

Mr.  Emanuel's  price  list  quotes  for  1865,  in  pounds  sterling  and 
shillings : 

A  Brilliant,  weighing  i  of  a  carat, £  stg.      5  10*.  5d. 

f     "        "     "          9  10 

"  "         1       "        "...."  18 

"  "         li     "        "  "  28 

ft  «  -Jl  ((  «  ft  gg 

**<  "         If     "        "     "        48 

'• ~  \  «-•'•.      2       "        «     "        65 

•^-:         w-     2i    «  \-:-*  ".£,':..;•*;•'    70 

*"'«''-"'  "         2£     "        "     "        88 

V-.--<      •  .•.•,"/'    2f    "      "...."    100 

>•         3  "  "...."  125 

3i  "  "     ....     «  135 

3i  "  "     ...'.     "  150 

3f  "  "...."  175 

•'.'"*'.     4     "".;>;  *  w    220 

4J  "  "     "  230 

4i  "  "     "  250 

4|  "  "...."  280 

5  "  "...."  320 

The  Rose  Diamond,  which  is  not  much  in  use  in  Europe,  but  more 
in  South  America,  has  not  a  very  fixed  value.  The  small  Rose  Dia- 
monds, if  under  40  to  the  carat,  are  worth  about  five  shillings  each  ; 
above  that  size,  and  up  to  one  carat,  bring  from  £9  stg.  to  £11  stg. 
the  carat. 

Ruby  and  Emerald. — Both  these  gems,  when  really  fine,  free  from 
any  defect,  in  color  or  size,  are  worth  as  much  as  Diamonds  of  the 
same  weight.  ^ 

A  fair  Ruby  is  worth  from  $30  to  $40  per  carat.  A  fine  and  pure 
Ruby,  well  spread  and  proportioned,  is  worth,  according  to  Mr. 
Emanuel — 

Of  1  carat, £  stg.    14  to   20 

H   "     "        25  to    35 

2  " "        70  to    80 

3  "     "      200  to  250 

4  "     "      400to450 

And  those  below  the  weight  of  one  carat  range  from  £2  to  £8  stg. 
per  carat ;  while  stones  of  greater  weight  than  four  carats  are  of 


504  APPENDIX. 

Bucli  exceptional  occurrence  as  to  command  fancy  prices.     Again,  a 
Ruby  of  four  carats,  but  of  a  pale  color,  may  not  be  worth  £12  stg. 

The  Emerald  is  so  rarely  found  perfect  that  the  saying,  "An 
Emerald  without  a  flaw,"  has  passed  into  a  proverb.  A  good  Em- 
erald is  at  the  present  day  worth  more  than  a  Ruby,  on  account  of 
the  pleasing  effect  it  has  both  by  day  and  candle-light,  and  is  a  very 
favorite  gem ;  stands  high  in  value ;  but  the  Emeralds  found  lat- 
terly and  brought  into  market  are  far  inferior  to  those  formerly 
found.  A  good  Emerald  is  worth  in  this  country  $40  to  $50  per 
carat.  In  England  the  price  ranges  from  5s.  to  £15  stg.  per  carat ; 
but  one  of  deep,  rich  grass-green  color,  clear  and  free  from  flaws, 
may  bring  from  £20  to  £40  stg.  per  carat. 

Sapphire. — A  fine,  perfect,  evenly  colored  spread  Sapphire,  weigh- 
ing one  carat,  of  a  deep  rich  blue  color,  by  night  as  well  as  by  day, 
is  worth  £20  stg. ;  it  does  not,  however,  increase  so  much  in  isalue 
in  proportion  to  its  size. 

The  Spinel  or  Balajs-Ruby,  if  of  good  quality,  is  sold  from  10s.  to 
£8  stg.  per  carat.  The  value  is  extremely  uncertain  and  variable ; 
it  depends  entirely  on  caprice  and  fashion. 

The  Topaz. — The  commercial  nature  of  the  Topaz  as  a  jewel  is 
entirely  fictitious.  A  very  fine  stone  can  now  be  bought  for  a  few 
shillings  sterling,  whilq  it  would  have  brought  a  great  deal  more 
when  in  fashion.  Pink  Topaz  brings  from  £2  stg.  to  £20  stg.  per 
ounce,  the  price  depending  on  the  depth  of  the  pink  color. 

Beryl  or  Aquamarine.— The  commercial  value  of  this  stone  is 
trifling,  and  is  used  mostly  for  imitation  jewelry.  Zircon,  Hyacinth 
or  Jacinth,  are  also  called  Jar  goon.  These  stones,  are  identically  the 
same,  but  differ  in  color ;  the  red  varieties  are  sometimes  sold  for 
inferior  Rubies.  The  Jargoon  is  frequently  cut  in  the  form  of  a  Rose 
Diamond,  which  is  flat  at  the  bottom  and  pointed  at  the  top.  The 
price  is  purely%rbitrary. 

The  Garnet,  Essonite,  Pyrope  and  Almandine. — The  color  of  the 
Syrian  Garnet,  being  of  deep  crimson,  is  at  present  much  in  vogue, 
and  commands  a  fair  price,  say  from  $1  to  $2  per  carat. 

The  Bohemian  Garnets  are  worth  from  $15  to  $25  per  ounce. 

Amethyst. — A  fine  deep-colored  stone,  of  the  size  of  a  twenty-five 
cent  piece,  is  worth  from  $80  to  $100  per  ounce ;  smaller  sizes  and 
inferior  qualities  are  sold  for  50  cents  to  $10  apiece. 

Peridote,  Chrysolite.— The  value  of  both  stones  is  but  small ;  fair 
specimens  of  good  size  may  be  bought  at  from  25c.  to  $5  per  carat. 

Turquoise. — The  Persian  is  much  used  in  jewelry ;  small,  clear 


APPENDIX.  505 

stones  bring  from  sixpence  to  20*.  stg.  each,  while  a  fine  Ring 
stone  will  realize  from  £10  stg.  to  £40  stg.  Large  Turquoise,  of 
good  quality  and  fine  color,  are  extremely  rare,  and  realize  extrava- 
gant prices. 

Opal. — The  value  of  the  precious  Opal  depends  entirely  on  the 
brilliancy  and  play  of  its  colors  ;  large,  fine  gems,  of  extraordinary 
beauty,  have  brought  fabulous  prices.  They  are  not  sold  by  the 
carat,  but  by  the  piece. 

Coral. — The  red  Coral,  which  formerly  was  the  most  valuable,  is 
now  worth  far  less  than  the  color  which  was  formerly  worthless. 
The  pale,  delicate  pink,  similar  to  that  of  the  inside  of  the  pale  rose 
leaf,  is  sought  after,  but  very  scarce ;  a  Coral  of  this  tint  is  very 
valuable.  £48  stg.  per  ounce  has  lately  been  paid  in  London.  A 
large  bead  or  drop  will  readily  realize  from  £30  stg.  to  £40  stg.  ; 
small  pieces,  however,  may  be  had  for  $4  to  $6  per  ounce. 

Pearls. — The  value  for  perfectly  pure  round  Pearls,  of  a  smooth 
and  lustrous  skin,  perfectly  free  from  specks  or  discoloration  of  any 

sort,  of  small  size,  is  from $1  to  $2  a  grain. 

4  grain  Pearls, 2  to     3         " 

6    "          "       5  to    6 

10    "          "       8  to  10 

The  following  is  Mr.  Emanuel's  table  of  prices  of  Pearls,  viz. : 
A  Pearl  of  1  grain  is  worth  from   2*.        to      2*.  Qd. 
"         2      "  "        "      6s.  Qd.  to      7«.  Qd. 

3  "  "        "     12*.        to    16*. 

4  "  "        "     22*.        to    28*. 

5  "  "        "     35*.        to    48*. 

6  "  "        "     55*.        to    65*. 
8      "             "        "     90*.        to  110*. 

10  "  "  "  £  8  stg.  to  £    9  stg. 

"       12  "  "  "  £12  "  to  £  15    " 

"       14  "  «  "  £15  "  to  £  18    " 

16  "  "  "  £20  "  to  £  30    " 

18  "  "  "  £30  "  to  £  40    " 

20  "  "  "  £40  "  to  £  50    " 

24  "  «  "  £60  "  to  £  70    " 

30  "  "  "  £80  "  to  £100  " 

Round  Pearls  above  the  latter  weight  are  of  such  rare  occurrence 
and  command  such  exceptional  prices,  that  it  would  be  useless  to 
attempt  any  scale  of  valuation. 


14  DAY  USE 


RETU 


RROWED 


RN  TQJ)ESK  ERO]VOWai££] 

LOAN  IDE.?!. 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall. 


22Jun'fiOFW 

JUN4    1957    T 

R  —    .      - 

REC'D  LD 

JUN  8    19fin 

MAY  °9  1957 

IfiHl    w  **    IOv» 

/9l  y 

3Sep'58CSf 

<^Cl  6//f  g 
_    " 

- 

"wyasr- 

•saM: 

22Ja" 

REC'D  T 

? 

LD  21-100m-6,'56 
(B9311slO)476 


University  of  California 
Berkeley 


YB   ,'5203 


' 


